U.S. patent application number 15/006796 was filed with the patent office on 2016-07-28 for curable resin composition, cured product thereof, and semiconductor device using the same.
The applicant listed for this patent is Central Glass Company, Limited. Invention is credited to Junya NAKATSUJI, Masafumi ODA, Tsuyoshi OGAWA, Yutaka SUGITA.
Application Number | 20160215168 15/006796 |
Document ID | / |
Family ID | 55409672 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160215168 |
Kind Code |
A1 |
ODA; Masafumi ; et
al. |
July 28, 2016 |
Curable Resin Composition, Cured Product Thereof, and Semiconductor
Device Using the Same
Abstract
According to one aspect of the present invention, there is
provided a curable resin composition including at least: a
polysiloxane compound having, in a molecule thereof, at least two
functional groups selected from the group consisting of silanol
groups and alkoxysilyl groups as a component (A-1); and silica
whose extract water has a pH of 6.1 or lower at 25.degree. C. as a
component (B), wherein the amount of the component (B) relative to
the total amount of the components (A-1) and (B) is in a range of
70 to 97 mass %. This curable resin composition is able to, even
when formed into various shapes and sizes, prevent foaming during
curing and thus is suitable as an encapsulant material for a
semiconductor element.
Inventors: |
ODA; Masafumi; (Fujimi-shi,
JP) ; NAKATSUJI; Junya; (Fujimi-shi, JP) ;
SUGITA; Yutaka; (Fujimino-shi, JP) ; OGAWA;
Tsuyoshi; (Iruma-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Central Glass Company, Limited |
Ube-shi |
|
JP |
|
|
Family ID: |
55409672 |
Appl. No.: |
15/006796 |
Filed: |
January 26, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 2924/19107
20130101; H01L 2224/48247 20130101; C08G 77/80 20130101; H01L
2224/48091 20130101; H01L 2224/48227 20130101; H01L 23/49568
20130101; C08K 3/36 20130101; C08G 77/18 20130101; C08G 77/04
20130101; C08K 3/36 20130101; H01L 2224/73265 20130101; H01L
2924/0002 20130101; C08L 83/06 20130101; C08K 3/36 20130101; H01L
2924/00 20130101; H01L 2924/00014 20130101; C09D 183/04 20130101;
H01L 2924/0002 20130101; H01L 23/295 20130101; C09D 183/04
20130101; H01L 23/296 20130101; H01L 23/49503 20130101; H01L
23/4952 20130101; H01L 2224/48091 20130101; H01L 23/3121 20130101;
H01L 21/56 20130101; C08G 77/16 20130101; H01L 23/49562
20130101 |
International
Class: |
C09D 183/04 20060101
C09D183/04; H01L 23/29 20060101 H01L023/29; C08K 3/36 20060101
C08K003/36; H01L 21/56 20060101 H01L021/56; C08G 77/00 20060101
C08G077/00; C08G 77/04 20060101 C08G077/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 26, 2015 |
JP |
PCT/JP2015/051959 |
Claims
1. A curable resin composition comprising at least: component
(A-1): a polysiloxane compound having, in a molecule thereof, at
least two functional groups selected from the group consisting of
silanol groups and alkoxysilyl groups; and component (B): silica
whose extract water has a pH of 6.1 or lower at 25.degree. C.,
wherein the amount of the component (B) relative to the total
amount of the components (A-1) and (B) is in a range of 70 to 97
mass %.
2. The curable resin composition according to claim 1, wherein the
polysiloxane compound contained as the component (A-1) has at least
a structural unit of the general formula [1]
[R.sup.1.sub.mSiO.sub.n/2] [1] where R.sup.1 each independently
represents a hydrogen atom, a C.sub.1-C.sub.10 linear alkyl group,
a C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group, a C.sub.2-C.sub.10 linear alkenyl group, a
C.sub.3-C.sub.10 branched alkenyl group, a C.sub.3-C.sub.10 cyclic
alkenyl group or a C.sub.5-C.sub.10 aryl group; a part or all of
hydrogen atoms of the alkyl group, the alkenyl group or the aryl
group may be substituted by a halogen atom; a part of carbon atoms
of the alkyl group, the alkenyl group or the aryl group may be
replaced by at least one kind selected from the group consisting of
a nitrogen atom, an oxygen atom and a silicon atom; the halogen
atom is at least one kind selected from the group consisting of a
fluorine atom, a chlorine atom, a bromine atom and an iodine atom;
when there are a plurality of R.sup.1, R.sup.1 can be of the same
kind or different kinds; an oxygen atom of the structural unit of
the general formula [1] is a siloxane bond-forming oxygen atom or a
hydroxyl oxygen atom; and m and n each independently represent an
integer of 1 to 4 and satisfy a relationship of m+n=4.
3. The curable resin composition according to claim 2, wherein
R.sup.1 is a C.sub.1-C.sub.10 linear alkyl group, a
C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group or a C.sub.5-C.sub.10 aryl group.
4. The curable resin composition according to claim 2, wherein
R.sup.1 is a methyl group or a phenyl group.
5. The curable resin composition according to claim 2, wherein the
polysiloxane compound contained as the component (A-1) has the
structural unit of the general formula [1] and a structural unit of
the general formula [2] [SiO.sub.4/2] [2] where an oxygen atom of
the structural unit of the general formula [2] is a siloxane
bond-forming oxygen atom or a hydroxyl oxygen atom.
6. The curable resin composition according to claim 1, wherein the
total amount of silanol and alkoxysilyl groups in the component
(A-1) is in a range of 1 to 15 mmol/g.
7. The curable resin composition according to claim 1, wherein the
component (B) contains two or more kinds of silica.
8. The curable resin composition according to claim 7, wherein the
two or more kinds of silica are selected from the group consisting
of crystalline silica, natural fused silica, synthetic fused
silica, deflagration silica, fumed silica, sol-gel silica, flame
fused silica and precipitated silica.
9. The curable resin composition according to claim 1, wherein the
silica contained as the component (B) has a median particle size of
0.02 to 500 .mu.m.
10. The curable resin composition according to claim 1, wherein the
silica contained as the component (B) shows a plurality of
frequency peaks in particle size distribution analysis.
11. The curable resin composition according to claim 1, wherein the
silica contained as the component (B) includes silica particles
having a particle size of 3 .mu.m or smaller.
12. The curable resin composition according to claim 1, wherein the
silica contained as the component (B) is chemically unmodified.
13. The curable resin composition according to claim 1, further
comprising at least one kind selected from the group consisting of
an inorganic filler, a heat-resistant resin, a mold release agent,
a pigment, a flame retardant, a curing catalyst and an
anti-blocking agent.
14. The curable resin composition according to claim 13, further
comprising a coupling agent.
15. The curable resin composition according to claim 1, wherein the
curable resin composition has a spiral flow length of 5 to 180 cm
as determined according to Japan Electrical Insulating and Advanced
Performance Materials Industrial Association Standard T901 under
the conditions of a temperature of 180.degree. C., a molding
pressure of 6.9 MPa and a molding time of 3 minutes.
16. A method for preparing the curable resin composition according
to claim 1, comprising mixing the component (A-1) with the
component (B) such that the amount of the component (B) relative to
the total amount of the component (A-1) and the component (B) is in
a range of 70 to 97 mass %.
17. The method for preparing the curable resin composition
according to claim 16, wherein the curable resin composition is
prepared by mixing the component (A-1), the component (B) and at
least one kind selected from the group consisting of an inorganic
filler, a heat-resistant resin, a mold release agent, a pigment, a
flame retardant, a curing catalyst and an anti-blocking agent.
18. The method for preparing the curable resin composition
according to claim 16, wherein the curable resin composition is
prepared by mixing the component (A-1), the component (B), at least
one kind selected from the group consisting of an inorganic filler,
a heat-resistant resin, a mold release agent, a pigment, a flame
retardant, a curing catalyst and an anti-blocking agent, and a
coupling agent.
19. A tableted product of the curable resin composition according
to claim 1.
20. A cured product of the curable resin composition according to
claim 1.
21. The cured product according to claim 20, wherein the cured
product has a thickness of 1 mm or greater.
22. The cured product according to claim 20, wherein the cured
product has a thickness of 2 mm or greater.
23. The cured product according to claim 20, wherein the cured
product has a thickness of 4 mm or greater.
24. A semiconductor device comprising at least a semiconductor
element encapsulated by the cured product according to claim
20.
25. The semiconductor device according to claim 24, wherein the
semiconductor element is a power semiconductor element.
26. A method of encapsulating a semiconductor element, comprising
curing the curable resin composition according to claim 1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a curable resin composition
suitable as a raw material of encapsulants for semiconductor
elements, especially power semiconductor elements, a cured product
of the curable resin composition and a semiconductor device using
the curable resin composition or cured product.
BACKGROUND OF THE INVENTION
[0002] There is a tendency that the amount of heat generated by
semiconductor devices increases with improvement in the
functionality and performance of electronic equipment. In
particular, power semiconductor devices for power and supply
control are required to achieve high-voltage and large-current
characteristics. Devices having mounted thereon silicon carbide
(SiC) semiconductor elements, gallium nitride (GaN) semiconductor
elements etc. are expected as the next-generation power
semiconductor devices. It is assumed that the full potential of
these devices are exploited by stable operations at about
250.degree. C. Under such circumstances, the heat-resistant
temperature required of peripheral components such as encapsulants
are becoming high.
[0003] Conventionally, epoxy resin compositions are used as raw
materials of encapsulants for power semiconductor elements. It is
generally known that cured products of epoxy resin compositions,
when left for a long time under temperature conditions of
150.degree. C. or higher, show deteriorations in weight and
mechanical strength. Various studies have thus been made to improve
the heat resistance of cured epoxy resin products. For example,
Japanese Laid-Open Patent Application Publication No. 2014-9936
discloses an epoxy resin-containing cured product applicable up to
temperatures near 180.degree. C. However, the heat resistance of
this cured product is not yet sufficient as required for the
operations of SiC and GaN power semiconductor devices at about
250.degree. C.
[0004] Silicone resin compositions are also widely used as
encapsulants for power semiconductor elements. As methods for
obtaining cured products of silicon resin compositions, there are
known a method using hydrosilylation between a hydrosilyl group and
an alkenyl group (see, for example, Japanese Laid-Open Patent
Application Publication No. 2008-27966 and No. 2005-146191), a
method using polymerization reaction by a reactive functional group
such as epoxy group (see, for example, International Patent
Application Publication No. 2004/072150) and the like. In these
methods, however, the cross linkages of the cured products are poor
in thermal stability so that the cured products are not always
suitable for uses where the cured products are required to have
heat resistance at about 250.degree. C. for a long time.
[0005] As another curing method, there is also known a method using
so-called condensation and, more specifically, at least one of
dehydration condensation between silanol groups, dealcoholization
condensation between a silanol group and an alkoxysilyl group and
dehydrocondensation of a silanol group and a hydrosilyl group.
Polysiloxane compounds usable as raw materials for the production
of cured products by such a condensation curing method are called
condensation type polysiloxane compounds. It is known that cured
products of condensation type polysiloxane compounds have both main
chain and cross-linkage structures constituted only by chemically
stable siloxane bond and thus show very high heat resistance.
Further, the condensation curing method enables forming and curing
at temperatures of 200.degree. C. or lower and thus can suitably be
utilized for encapsulation of semiconductor elements with
heat-sensitive components. It is consequently possible to attain
high material selectivity by the condensation curing of
condensation type polysiloxane compounds as compared to the case of
using the other heat-resistant materials such as ordinary polyimide
resin and molten glass that need to be subjected to forming and
curing at temperatures exceeding 200.degree. C. However, the
condensation curing method has the problem of the occurrence of
foaming in the cured product by generation of gas (water, alcohol
and/or hydrogen) during curing. The foaming is regarded as a
problem since the occurrence of foaming leads to deteriorations in
the adhesion, mechanical strength, gas barrier function and
insulating property of the cured product. It is essentially
difficult to solve such a foaming problem due to the nature of the
condensation reaction.
[0006] Various studies have been made to suppress the occurrence of
foaming in cured products of condensation type polysiloxane
compositions. For example, Japanese Laid-Open Patent Application
Publication No. 2009-256670 discloses a condensation type
polysiloxane composition capable of being formed into a cured
product with an average thickness of 1.2 mm or smaller. It is
discussed in this patent publication that the occurrence of foaming
in the cured product can be reduced by decreasing the film
thickness of the composition. Furthermore, Japanese Laid-Open
Patent Application Publication No. 2011-219729 discloses a
condensation type polysiloxane composition containing
polydimethylsiloxane having two silanol groups bonded to both
terminal ends thereof. In this composition, the condensation site
of the polysiloxane is decreased so as to control the thickness of
the cured product to 1 mm or smaller reducing the amount of gas
generation during curing.
SUMMARY OF THE INVENTION
[0007] As mentioned above, cured products of condensation type
polysiloxane compositions are expected to be useful as encapsulants
for SiC and GaN power semiconductor elements. By forming a film of
condensation type polysiloxane composition and curing the resulting
polysiloxane composition film, it is feasible to suppress the
occurrence of foaming in the cured product. It is however very
difficult to suppress the occurrence of foaming at the time of
producing a cured product of condensation type polysiloxane
composition in bulk form of greater than predetermined thickness
and size. Although the thickness and size required of cured
products as encapsulants for power semiconductor elements vary,
there are many cured products available in thicknesses of 4 mm or
greater and width and length dimensions of 10 mm or greater for use
as semiconductor encapsulants. Accordingly, there is a limit on the
application of cured products of condensation type polysiloxane
compositions for use as encapsulants.
[0008] The present invention has been made in view of the above
circumstances. It is an object of the present invention to provide
a condensation curable resin composition, even when formed into
various shapes and sizes, free of the occurrence of foaming during
curing. It is also an object of the present invention to provide a
cured product of the curable resin composition and a semiconductor
device using the cured product.
[0009] As a result of extensive researches, the present inventors
have found that it is possible to achieve the above object by the
use of a curable resin composition containing at least a specific
polysiloxane compound as a component (A) and silica whose extract
water has a pH of 6.1 or lower at 25.degree. C. as a component (B)
such that the amount of the component (B) relative to the total
amount of the components (A) and (B) is in the range of 70 to 97
mass %. Based on this finding, the present inventors have
accomplished a condensation curable resin composition, even when
formed into various shapes and sizes, free of the occurrence of
foaming during curing
[0010] Namely, the present invention provides a curable resin
composition free of the occurrence of foaming during curing even
when formed into various shapes and sizes. The present invention
also provides a cured product of the curable resin composition and
a semiconductor device using the curable resin composition or cured
product.
[0011] More specifically, the present invention includes the
following inventive aspects.
[0012] [Inventive Aspect 1]
[0013] A curable resin composition comprising at least:
[0014] component (A-1): a polysiloxane compound having, in a
molecule thereof, at least two functional groups selected from the
group consisting of silanol groups and alkoxysilyl groups; and
[0015] component (B): silica whose extract water has a pH of 6.1 or
lower at 25.degree. C.,
[0016] wherein the amount of the component (B) relative to the
total amount of the components (A-1) and (B) is in a range of 70 to
97 mass %.
[0017] [Inventive Aspect 2]
[0018] The curable resin composition according to Inventive Aspect
1, wherein the polysiloxane compound contained as the component
(A-1) contains has at least a structural unit of the general
formula [1]
[R.sup.1.sub.mSiO.sub.n/2] [1]
where R.sup.1 each independently represents a hydrogen atom, a
C.sub.1-C.sub.10 linear alkyl group, a C.sub.3-C.sub.10 branched
alkyl group, a C.sub.3-C.sub.10 cyclic alkyl group, a
C.sub.2-C.sub.10 linear alkenyl group, a C.sub.3-C.sub.10 branched
alkenyl group, a C.sub.3-C.sub.10 cyclic alkenyl group or a
C.sub.5-C.sub.10 aryl group; a part or all of hydrogen atoms of the
alkyl group, the alkenyl group or the aryl group may be substituted
by a halogen atom; a part of carbon atoms of the alkyl group, the
alkenyl group or the aryl group may be replaced by at least one
kind selected from the group consisting of a nitrogen atom, an
oxygen atom and a silicon atom; the halogen atom is at least one
kind selected from the group consisting of a fluorine atom, a
chlorine atom, a bromine atom and an iodine atom; when there are a
plurality of R.sup.1, R.sup.1 can be of the same kind or different
kinds; an oxygen atom of the structural unit of the general formula
[1] is a siloxane bond-forming oxygen atom or a hydroxyl oxygen
atom; and m and n each independently represent an integer of 1 to 4
and satisfy a relationship of m+n=4.
[0019] [Inventive Aspect 3]
[0020] The curable resin composition according to Inventive Aspect
2, wherein R.sup.1 is a C.sub.1-C.sub.10 linear alkyl group, a
C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group or a C.sub.5-C.sub.10 aryl group.
[0021] [Inventive Aspect 4]
[0022] The curable resin composition according to Inventive Aspect
2, wherein R.sup.1 is a methyl group or a phenyl group.
[0023] [Inventive Aspect 5]
[0024] The curable resin composition according to any one of
Inventive Aspects 2 to 4, wherein the polysiloxane compound
contained as the component (A-1) has the structural unit of the
general formula [1] and a structural unit of the general formula
[2]
[SiO.sub.4/2] [2]
where an oxygen atom of the structural unit of the general formula
[2] is a siloxane bond-forming oxygen atom or a hydroxyl oxygen
atom.
[0025] [Inventive Aspect 6]
[0026] A curable resin composition comprising at least:
[0027] component (A-2): a polysiloxane compound obtained by
hydrolysis and polycondensation of at least one kind of
alkoxysilane compound of the general formula [3]
(R.sup.1).sub.ySi(OR.sup.2).sub.4-y [3]
where R.sup.1 each independently represents a hydrogen atom, a
C.sub.1-C.sub.10 linear alkyl group, a C.sub.3-C.sub.10 branched
alkyl group, a C.sub.3-C.sub.10 cyclic alkyl group, a
C.sub.2-C.sub.10 linear alkenyl group, a C.sub.3-C.sub.10 branched
alkenyl group, a C.sub.3-C.sub.10 cyclic alkenyl group or a
C.sub.5-C.sub.10 aryl group; a part or all of hydrogen atoms of the
alkyl group, the alkenyl group or the aryl group may be substituted
by a halogen atom; a part of carbon atoms of the alkyl group, the
alkenyl group or the aryl group may be replaced by at least one
kind selected from the group consisting of a nitrogen atom, an
oxygen atom and a silicon atom; the halogen atom is at least one
kind selected from the group consisting of a fluorine atom, a
chlorine atom, a bromine atom and an iodine atom; when there are a
plurality of R.sup.1, R.sup.1 can be of the same kind or different
kinds; R.sup.2 each independently represents a C.sub.1-C.sub.4
linear alkyl group or a C.sub.3-C.sub.4 branched alkyl group; when
there are a plurality of R.sup.2, R.sup.2 can be of the same kind
or different kinds; and y represents an integer of 1 to 3; and
[0028] component (B): silica whose extract water has a pH of 6.1 or
lower at 25.degree. C.,
[0029] wherein the amount of the component (B) relative to the
total amount of the components (A-2) and (B) is in a range of 70 to
97 mass %.
[0030] [Inventive Aspect 7]
[0031] The curable resin composition according to Inventive Aspect
6, wherein R.sup.1 is a C.sub.1-C.sub.10 linear alkyl group, a
C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group or a C.sub.5-C.sub.10 aryl group.
[0032] [Inventive Aspect 8]
[0033] The curable resin composition according to Inventive Aspect
6, wherein R.sup.1 is a methyl group or a phenyl group.
[0034] [Inventive Aspect 9]
[0035] The curable resin composition according to any one of
Inventive Aspects 6 to 8, wherein the polysiloxane compound
contained as the component (A-2) is a polysiloxane compound
obtained by hydrolysis and polycondensation of at least one kind of
alkoxysilane compound of the general formula [3] and at least one
kind of alkoxysilane compound of the general formula [4]
Si(OR.sup.2).sub.4 [4]
where R.sup.2 each independently represents a C.sub.1-C.sub.4
linear alkyl group or a C.sub.3-C.sub.4 branched alkyl group; and,
when there are a plurality of R.sup.2, R.sup.2 can be of the same
kind or different kinds.
[0036] [Inventive Aspect 10]
[0037] The curable resin composition according to any one of
Inventive Aspects 1 to 5, wherein the total amount of silanol and
alkoxysilyl groups in the component (A-1) is in a range of 1 to 15
mmol/g.
[0038] [Inventive Aspect 11]
[0039] The curable resin composition according to any one of
Inventive Aspects 6 to 9, wherein the total amount of silanol and
alkoxysilyl groups in the component (A-2) is in a range of 1 to 15
mmol/g.
[0040] [Inventive Aspect 12]
[0041] The curable resin composition according to any one of
Inventive Aspects 1 to 11, wherein the component (B) contains two
or more kinds of silica.
[0042] [Inventive Aspect 13]
[0043] The curable resin composition according to Inventive Aspect
12, wherein the two or more kinds of silica are selected from the
group consisting of crystalline silica, natural fused silica,
synthetic fused silica, deflagration silica, fumed silica, sol-gel
silica, flame fused silica and precipitated silica.
[0044] [Inventive Aspect 14]
[0045] The curable resin composition according to any one of
Inventive Aspects 1 to 13, wherein the silica contained as the
component (B) has a median particle size of 0.02 to 500 .mu.m.
[0046] [Inventive Aspect 15]
[0047] The curable resin composition according to any one of
Inventive Aspects 1 to 14, wherein the silica contained as the
component (B) shows a plurality of frequency peaks in particle size
distribution analysis.
[0048] [Inventive Aspect 16]
[0049] The curable resin composition according to any one of
Inventive Aspects 1 to 15, wherein the silica contained as the
component (B) includes silica particles having a particle size of 3
.mu.m or smaller.
[0050] [Inventive Aspect 17]
[0051] The curable resin composition according to any one of
Inventive Aspects 1 to 16, wherein the silica contained as the
component (B) is chemically unmodified.
[0052] [Inventive Aspect 18]
[0053] The curable resin composition according to any one of
Inventive Aspects 1 to 17, further comprising at least one kind
selected from the group consisting of an inorganic filler, a
heat-resistant resin, a mold release agent, a pigment, a flame
retardant, a curing catalyst and an anti-blocking agent.
[0054] [Inventive Aspect 19]
[0055] The curable resin composition according to Inventive Aspect
18, wherein the inorganic filler is at least one kind selected from
the group consisting of silica different from the silica contained
as the component (B), alumina, titania, zirconia, clay mineral,
glass, zinc oxide, boron nitride, aluminum nitride, calcium
carbonate, magnesium carbonate, zirconium phosphate, zirconium
phosphate tungstate and carbon isotope.
[0056] [Inventive Aspect 20]
[0057] The curable resin composition according to Inventive Aspect
18, wherein the heat-resistant resin is at least one kind selected
from the group consisting of nanocellulose, aramid fiber, carbon
fiber, PEEK resin and polyimide.
[0058] [Inventive Aspect 21]
[0059] The curable resin composition according to Inventive Aspect
18, wherein the mold release agent is at least one kind selected
from the group consisting of Candellia wax, Carnauba wax, Rice wax,
Montana wax, paraffin wax, synthetic wax, tetrafluoroethylene
resin, tetrafluoroethylene-perfluoroalkoxyethyelene copolymer
resin, tetrafluoroethylene-hexafluoropropylene copolymer resin,
tetrafluoroethylene-ethylene copolymer resin, vinylidene fluoride
resin, dimethylsilicone and fluorosilicone.
[0060] [Inventive Aspect 22]
[0061] The curable resin composition according to Inventive Aspect
18, wherein the pigment is at least one kind selected from the
group consisting of carbon black, hydrozincite, white lead,
lithopone, titanium dioxide, precipitated barium sulfate, barite
powder, red lead, red iron oxide, chrome yellow, zinc yellow,
ultramarine blue, prussian blue, phthalocyanine, polycyclic pigment
and azo pigment.
[0062] [Inventive Aspect 23]
[0063] The curable resin composition according to Inventive Aspect
18, wherein the flame retardant is at least one kind selected from
the group consisting of a halogen flame retardant, a phosphorus
flame retardant, a metal hydroxide flame retardant and an antimony
flame retardant.
[0064] [Inventive Aspect 24]
[0065] The curable resin composition according to Inventive Aspect
18, wherein the curing catalyst is an acid catalyst, a base
catalyst or a metal complex catalyst.
[0066] [Inventive Aspect 25]
[0067] The curable resin composition according to Inventive Aspect
24, wherein the acid catalyst is at least one kind selected from
the group consisting of acetic acid, propionic acid,
trifluoroacetic acid, methanesulfonic acid,
trifluoromethanesulfonic acid, formic acid, oxalic acid, maleic
acid, camphorsulfonic acid, benzenesulfonic acid, tosic acid,
hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and
boric acid.
[0068] [Inventive Aspect 26]
[0069] The curable resin composition according to Inventive Aspect
24, wherein the base catalyst is at least one kind selected from
the group consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene,
diethylamine, triethylamine, imidazole, pyridine,
triphenylphosphine, sodium hydroxide, potassium hydroxide, lithium
hydroxide, magnesium hydroxide, sodium carbonate, potassium
carbonate, cesium carbonate and sodium hydrocarbonate.
[0070] [Inventive Aspect 27]
[0071] The curable resin composition according to Inventive Aspect
24, wherein the metal complex catalyst is at least one kind
selected from the group consisting of zinc octoate, zinc benzoate,
zinc p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminum
chloride, aluminum perchlorate, aluminum phosphate, aluminum
triisopropoxide, aluminum acetylacetonate, aluminum
butoxybisethylacetoacetate, tetrabutyl titanate, tetraisopropyl
titanate, tin octoate, tin naphthenate and cobalt naphthenate.
[0072] [Inventive Aspect 28]
[0073] The curable resin composition according to Inventive Aspect
18, wherein the anti-blocking agent is at least one kind selected
from the group consisting of lauric acid, myristic acid, palmitic
acid, margaric acid, stearic acid, arachidic acid, behenic acid, Li
salt of stearic acid, Na salt of stearic acid, Mg salt of stearic
acid, K salt of stearic acid, Ca salt of stearic acid, Ba salt of
stearic acid, Al salt of stearic acid, Zn salt of stearic acid, Fe
salt of stearic acid, Ca salt of lauric acid, Ba salt of lauric
acid, Zn salt of lauric acid, Ca salt of behenic acid, Ba salt of
behenic acid, Zn salt of behenic acid, Ca salt of 12-hydroxystearic
acid, Mg salt of 12-hydroxystearic acid, Zn salt of
12-hydroxystearic acid, aluminum silicate, crystalline silica,
natural fused silica, synthetic fused silica, deflagration silica,
fumed silica, sol-gel silica, flame fused silica, precipitated
silica, zeolite, talc, kaolin, diatomite, polyethylene beads,
polytetrafluoroethylene, polymethyl methacrylate, acrylic resin and
silicon resin.
[0074] [Inventive Aspect 29]
[0075] The curable resin composition according to Inventive Aspect
18, further comprising a coupling agent.
[0076] [Inventive Aspect 30]
[0077] The curable resin composition according to Inventive Aspect
29, wherein the coupling agent is at least one kind selected from
the group consisting of methyltrimethoxysilane,
methyltriethoxysilane, phenyltrimethoxysilane,
phenyltriethoxysilane, ethyltrimethoxysilane,
propyltrimethoxysilane, isopropyltrimethoxysilane,
trifluoromethyltrimethoxysilane, pentafluoromethyltrimethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane, vinyltrimethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-methacryloxypropyltrimethoxysilane,
3-aminopropyltrimethoxysilane,
tris(trimethoxysilylpropyl)isocyanurate and
3-isocyanatepropyltriethoxysilane.
[0078] [Inventive Aspect 31]
[0079] The curable resin composition according to any one of
Inventive Aspects 1 to 30, wherein the curable resin composition
has a spiral flow length of 5 to 180 cm as determined according to
Japan Electrical Insulating and Advanced Performance Materials
Industrial Association Standard T901 under the conditions of a
temperature of 180.degree. C., a molding pressure of 6.9 MPa and a
molding time of 3 minutes.
[0080] [Inventive Aspect 32]
[0081] A preparation method of a curable resin composition,
[0082] the curable resin composition comprising at least:
[0083] component (A-1): a polysiloxane compound having, in a
molecule thereof, at least two functional groups selected from the
group consisting of silanol groups and alkoxysilyl groups, or
component (A-2): a polysiloxane compound obtained by hydrolysis and
polycondensation of at least one kind of alkoxysilane compound of
the general formula [3]
(R.sup.1).sub.ySi(OR.sup.2).sub.4-y [3]
where R.sup.1 each independently represents a hydrogen atom, a
C.sub.1-C.sub.10 linear alkyl group, a C.sub.3-C.sub.10 branched
alkyl group, a C.sub.3-C.sub.10 cyclic alkyl group, a
C.sub.2-C.sub.10 linear alkenyl group, a C.sub.3-C.sub.10 branched
alkenyl group, a C.sub.3-C.sub.10 cyclic alkenyl group or a
C.sub.5-C.sub.10 aryl group; a part or all of hydrogen atoms of the
alkyl group, the alkenyl group or the aryl group may be substituted
by a halogen atom; a part of carbon atoms of the alkyl group, the
alkenyl group or the aryl group may be replaced by at least one
kind selected from the group consisting of a nitrogen atom, an
oxygen atom and a silicon atom; the halogen atom is at least one
kind selected from the group consisting of a fluorine atom, a
chlorine atom, a bromine atom and an iodine atom; when there are a
plurality of R.sup.1, R.sup.1 can be of the same kind or different
kinds; R.sup.2 each independently represents a C.sub.1-C.sub.4
linear alkyl group or a C.sub.3-C.sub.4 branched alkyl group; when
there are a plurality of R.sup.2, R.sup.2 can be of the same kind
or different kinds; and y represents an integer of 1 to 3; and
[0084] component (B): silica whose extract water has a pH of 6.1 or
lower at 25.degree. C.,
[0085] the preparation method comprising mixing the component (A-1)
or (A-2) with the component (B) such that the amount of the
component (B) relative to the total amount of the component (A-1)
or (A-2) and the component (B) is in a range of 70 to 97 mass
%.
[0086] [Inventive Aspect 33]
[0087] The preparation method according to Inventive Aspect 32,
wherein two or more kinds of silica are mixed together in advance
and used as the component (B).
[0088] [Inventive Aspect 34]
[0089] The preparation method according to Inventive Aspect 33,
wherein the two or more kinds of silica are selected from the group
consisting of crystalline silica, natural fused silica, synthetic
fused silica, deflagration silica, fumed silica, sol-gel silica,
flame fused silica and precipitated silica.
[0090] [Inventive Aspect 35]
[0091] The preparation method according to any one of Inventive
Aspects 32 to 34, wherein the silica contained as the component (B)
has a median particle size of 0.02 to 500 .mu.m.
[0092] [Inventive Aspect 36]
[0093] The preparation method according to any one of Inventive
Aspects 32 to 35, wherein the silica contained as the component (B)
shows a plurality of frequency peaks in particle size distribution
analysis.
[0094] [Inventive Aspect 37]
[0095] The preparation method according to any one of Inventive
Aspects 32 to 36, wherein the silica contained as the component (B)
includes silica particles having a particle size of 3 .mu.m or
smaller.
[0096] [Inventive Aspect 38]
[0097] The preparation method according to any one of Inventive
Aspects 32 to 37, wherein the silica contained as the component (B)
is chemically unmodified.
[0098] [Inventive Aspect 39]
[0099] The preparation method according to any one of Inventive
Aspects 32 to 38, wherein the curable resin composition is prepared
by mixing the component (A-1) or (A-2), the component (B) and at
least one kind selected from the group consisting of an inorganic
filler, a heat-resistant resin, a mold release agent, a pigment, a
flame retardant, a curing catalyst and an anti-blocking agent.
[0100] [Inventive Aspect 40]
[0101] The preparation method according to any one of Inventive
Aspects 32 to 38, wherein the curable resin composition is prepared
by mixing the component (A-1) or (A-2), the component (B), at least
one kind selected from the group consisting of an inorganic filler,
a heat-resistant resin, a mold release agent, a pigment, a flame
retardant, a curing catalyst and an anti-blocking agent, and a
coupling agent.
[0102] [Inventive Aspect 41]
[0103] The preparation method according to Inventive Aspect 39 or
40, wherein the inorganic filler is at least one kind selected from
the group consisting of silica different from the silica contained
as the component (B), alumina, titania, zirconia, clay mineral,
glass, zinc oxide, boron nitride, aluminum nitride, calcium
carbonate, magnesium carbonate, zirconium phosphate, zirconium
phosphate tungstate and carbon isotope.
[0104] [Inventive Aspect 42]
[0105] The preparation method according to Inventive Aspect 39 or
40, wherein the heat-resistant resin is at least one kind selected
from the group consisting of nanocellulose, aramid fiber, carbon
fiber, PEEK resin and polyimide.
[0106] [Inventive Aspect 43]
[0107] The preparation method according to Inventive Aspect 39 or
40, wherein the mold release agent is at least one kind selected
from the group consisting of Candellia wax, Carnauba wax, Rice wax,
Montana wax, paraffin wax, synthetic wax, tetrafluoroethylene
resin, tetrafluoroethylene-perfluoroalkoxyethyelene copolymer
resin, tetrafluoroethylene-hexafluoropropylene copolymer resin,
tetrafluoroethylene-ethylene copolymer resin, vinylidene fluoride
resin, dimethyl silicone and fluorosilicone.
[0108] [Inventive Aspect 44]
[0109] The preparation method according to Inventive Aspect 39 or
40, wherein the pigment is at least one kind selected from the
group consisting of carbon black, hydrozincite, white lead,
lithopone, titanium dioxide, precipitated barium sulfate, barite
powder, red lead, red iron oxide, chrome yellow, zinc yellow,
ultramarine blue, prussian blue, phthalocyanine, polycyclic pigment
and azo pigment.
[0110] [Inventive Aspect 45]
[0111] The preparation method according to Inventive Aspect 39 or
40, wherein the flame retardant is at least one kind selected from
the group consisting of a halogen flame retardant, a phosphorus
flame retardant, a metal hydroxide flame retardant and an antimony
flame retardant.
[0112] [Inventive Aspect 46]
[0113] The preparation method according to Inventive Aspect 39 or
40, wherein the curing catalyst is an acid catalyst, a base
catalyst or a metal complex catalyst.
[0114] [Inventive Aspect 47]
[0115] The preparation method according to Inventive Aspect 46,
wherein the acid catalyst is at least one kind selected from the
group consisting of acetic acid, propionic acid, trifluoroacetic
acid, methanesulfonic acid, trifluoromethanesulfonic acid, formic
acid, oxalic acid, maleic acid, camphorsulfonic acid,
benzenesulfonic acid, tosic acid, hydrochloric acid, sulfuric acid,
nitric acid, phosphoric acid and boric acid.
[0116] [Inventive Aspect 48]
[0117] The preparation method according to Inventive Aspect 46,
wherein the base catalyst is at least one kind selected from the
group consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene,
diethylamine, triethylamine, imidazole, pyridine,
triphenylphosphine, sodium hydroxide, potassium hydroxide, lithium
hydroxide, magnesium hydroxide, sodium carbonate, potassium
carbonate, cesium carbonate and sodium hydrocarbonate.
[0118] [Inventive Aspect 49]
[0119] The preparation method according to Inventive Aspect 46,
wherein the metal complex catalyst is at least one kind selected
from the group consisting of zinc octoate, zinc benzoate, zinc
p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminum
chloride, aluminum perchlorate, aluminum phosphate, aluminum
triisopropoxide, aluminum acetylacetonate, aluminum
butoxybisethylacetoacetate, tetrabutyl titanate, tetraisopropyl
titanate, tin octoate, tin naphthenate and cobalt naphthenate.
[0120] [Inventive Aspect 50]
[0121] The preparation method according to Inventive Aspect 39 or
40, wherein the anti-blocking agent is at least one kind selected
from the group consisting of lauric acid, myristic acid, palmitic
acid, margaric acid, stearic acid, arachidic acid, behenic acid, Li
salt of stearic acid, Na salt of stearic acid, Mg salt of stearic
acid, K salt of stearic acid, Ca salt of stearic acid, Ba salt of
stearic acid, Al salt of stearic acid, Zn salt of stearic acid, Fe
salt of stearic acid, Ca salt of lauric acid, Ba salt of lauric
acid, Zn salt of lauric acid, Ca salt of behenic acid, Ba salt of
behenic acid, Zn salt of behenic acid, Ca salt of 12-hydroxystearic
acid, Mg salt of 12-hydroxystearic acid, Zn salt of
12-hydroxystearic acid, aluminum silicate, crystalline silica,
natural fused silica, synthetic fused silica, deflagration silica,
fumed silica, sol-gel silica, flame fused silica, precipitated
silica, zeolite, talc, kaolin, diatomite, polyethylene beads,
polytetrafluoroethylene, polymethyl methacrylate, acrylic resin and
silicon resin.
[0122] [Inventive Aspect 51]
[0123] The preparation method according to Inventive Aspect 40,
wherein the coupling agent is at least one kind selected from the
group consisting of methyltrimethoxysilane, methyltriethoxysilane,
phenyltrimethoxysilane, phenyltriethoxysilane,
ethyltrimethoxysilane, propyltrimethoxysilane,
isopropyltrimethoxysilane, trifluoromethyltrimethoxysilane,
pentafluoromethyltrimethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane, vinyltrimethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-methacryloxypropyltrimethoxysilane,
3-aminopropyltrimethoxysilane,
tris(trimethoxysilylpropyl)isocyanurate and
3-isocyanatepropyltriethoxysilane.
[0124] [Inventive Aspect 52]
[0125] The preparation method according to any one of Inventive
Aspects 32 to 51, wherein the curable resin composition has a
spiral flow length of 5 to 180 cm as determined according to Japan
Electrical Insulating and Advanced Performance Materials Industrial
Association Standard T901 under the conditions of a temperature of
180.degree. C., a molding pressure of 6.9 MPa and a molding time of
3 minutes.
[0126] [Inventive Aspect 53]
[0127] A tableted product of the curable resin composition
according to any one of Inventive Aspects 1 to 31.
[0128] [Inventive Aspect 54]
[0129] A cured product of the curable resin composition according
to any one of Inventive Aspects 1 to 31.
[0130] [Inventive Aspect 55]
[0131] The cured product according to Inventive Aspect 54, wherein
the cured product is obtained by subjecting the curable resin
composition to forming.
[0132] [Inventive Aspect 56]
[0133] The cured product according to Inventive Aspect 54 or 55,
wherein the cured product is obtained by subjecting the curable
resin composition to cast molding, compression molding or transfer
molding.
[0134] [Inventive Aspect 57]
[0135] The cured product according to any one of Inventive Aspects
54 to 56, wherein the curable resin composition is used in tablet
form and subjected to transfer molding.
[0136] [Inventive Aspect 58]
[0137] The cured product according to any one of Inventive Aspects
54 to 57, wherein the cured product has a thickness of 1 mm or
greater.
[0138] [Inventive Aspect 59] The cured product according to any one
of Inventive Aspects 54 to 58, wherein the cured product has a
thickness of 2 mm or greater.
[0139] [Inventive Aspect 60]
[0140] The cured product according to any one of Inventive Aspects
54 to 59, wherein the cured product has a thickness of 4 mm or
greater.
[0141] [Inventive Aspect 61]
[0142] An encapsulant for a semiconductor element, comprising the
cured product according to any one of Inventive Aspects 54 to
60.
[0143] [Inventive Aspect 62]
[0144] A semiconductor device comprising at least a semiconductor
element encapsulated by the cured product according to any one of
Inventive Aspects 54 to 60.
[0145] [Inventive Aspect 63]
[0146] The semiconductor device according to Inventive Aspect 62,
wherein the semiconductor element is a power semiconductor
element.
[0147] [Inventive Aspect 64]
[0148] A method of encapsulating a semiconductor element,
comprising curing the curable resin composition according to any
one of Inventive Aspects 1 to 31.
[0149] [Inventive Aspect 65]
[0150] Use of the curable resin composition according to any one of
Inventive Aspects 1 to 31 for encapsulating a semiconductor element
by curing the curable resin composition.
[0151] [Inventive Aspect 66]
[0152] The curable resin composition according to any one of
Inventive Aspects 1 to 31, wherein the curable resin composition is
a curable resin composition for encapsulating a semiconductor
element.
[0153] The curable resin composition of the present invention is,
even when formed into various shapes and sizes, free of the
occurrence of foaming during curing and thus is suitable as an
encapsulant material for a semiconductor element and, more
specifically, an encapsulant for a power semiconductor element.
BRIEF DESCRIPTION OF DRAWINGS
[0154] FIG. 1 is a schematic section view of a semiconductor device
according to one embodiment of the present invention.
[0155] FIG. 2 is a diagram showing heat resistance test results of
cured products in Experiment 3.
DESCRIPTION OF EMBODIMENTS
[0156] The present invention will be described in detail below. It
should be herein noted that: the technical scope of the present
invention is defined with reference to the following claims; and
the present invention is not limited to the following
embodiments.
[0157] [Curable Resin Composition]
[0158] According to the present invention, there is provided a
curable resin composition containing at least a specific
polysiloxane compound as a component (A) and a specific silica as a
component (B). The curable resin composition of the present
invention may contain a specific additive as an additional
component.
[0159] In the first embodiment of the present invention, the
curable resin composition contains the after-mentioned component
(A-1) as the component (A). On the other hand, the curable resin
composition contains the after-mentioned component (A-2) as the
component (A). In the present specification, features common to the
components (A-1) and (A-2) will be explained as features of the
component (A).
[0160] Hereinafter, the respective components of the curable resin
composition of the present invention will be explained in detail
below.
[0161] <Component (A): Polysiloxane Compound>
First Embodiment
[0162] The component (A-1) is a polysiloxane compound having, in a
molecule thereof, at least two functional groups selected from the
group consisting of silanol groups and alkoxysilyl groups. There is
no particular limitation on the kind of the polysiloxane compound
as long as the polysiloxane compound has at least two functional
groups selected from the group consisting of silanol groups and
alkoxysilyl groups in its molecule. It is feasible to use one kind
of polysiloxane compound alone or two or more kinds of polysiloxane
compounds in combination. The polysiloxane compound is obtained by
hydrolysis and polycondensation of at least one kind selected from
the group consisting of alkoxysilane compounds and chlorosilane
compounds. In the hydrolysis and polycondensation of the at least
one kind selected from the group consisting of alkoxysilane
compounds and chlorosilane compounds, a cyclic siloxane compound or
polydimethylsiloxane compound may be added.
[0163] For the production of a more suitable encapsulant for a
semiconductor element, especially for a power semiconductor
element, it is preferable that the component (A-1) contains a
polysiloxane compound having at least a structural unit of the
general formula [1] (hereinafter sometimes referred to as
"polysiloxane compound [1]"). The component (A-1) may contain any
polysiloxane compound other than the polysiloxane compound [1].
[R.sup.1.sub.mSiO.sub.n/2 ][1]
In the general formula [1], R.sup.1 each independently represents a
hydrogen atom, a C.sub.1-C.sub.10 linear alkyl group, a
C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group, a C.sub.2-C.sub.10 linear alkenyl group, a
C.sub.3-C.sub.10 branched alkenyl group, a C.sub.3-C.sub.10 cyclic
alkenyl group or a C.sub.5-C.sub.10 aryl group; a part or all of
hydrogen atoms of the alkyl group, the alkenyl group or the aryl
group may be substituted by a halogen atom; a part of carbon atoms
of the alkyl group, the alkenyl group or the aryl group may be
replaced by at least one kind selected from the group consisting of
a nitrogen atom, an oxygen atom and a silicon atom; the halogen
atom is at least one kind selected from the group consisting of a
fluorine atom, a chlorine atom, a bromine atom and an iodine atom;
when there are a plurality of R.sup.1, R.sup.1 can be of the same
kind or different kinds; an oxygen atom of the structural unit of
the general formula [1] is a siloxane bond-forming oxygen atom or a
hydroxyl oxygen atom; and m and n each independently represent an
integer of 1 to 4 and satisfy a relationship of m+n=4.
[0164] Examples of the C.sub.1-C.sub.10 linear alkyl group,
C.sub.3-C.sub.10 branched alkyl group or C.sub.3-C.sub.10 cyclic
alkyl group as R.sup.1 in the general formula [1] include methyl,
ethyl, propyl, butyl, hexyl, octyl, decyl, isopropyl, isobutyl,
sec-butyl, tert-butyl and cyclohexyl. Among others, methyl is
preferred.
[0165] Examples of the C.sub.2-C.sub.10 linear alkenyl group,
C.sub.3-C.sub.10 branched alkenyl group, or C.sub.3-C.sub.10 cyclic
alkenyl group as R.sup.1 in the general formula [1] include vinyl
and allyl.
[0166] Examples of the C.sub.5-C.sub.10 aryl group as R.sup.1 in
the general formula [1] include phenyl, 1-naphthyl and 2-naphthyl.
Among others, phenyl is preferred.
[0167] In order to improve the curing characteristics of the
curable resin composition and effectively suppress the occurrence
of cracking during encapsulation of a semiconductor element,
R.sup.1 is preferably a C.sub.1-C.sub.10 linear alkyl group, a
C.sub.3-C.sub.10 branched alkyl group, a C.sub.3-C.sub.10 cyclic
alkyl group or a C.sub.5-C.sub.10 aryl group in the structural unit
of the general formula [1]. It is particularly preferable that
R.sup.1 is a methyl group or a phenyl group in the structural unit
of the general formula [1].
[0168] The structural unit of the polysiloxane compound [1] where m
is 2 and n is 2, that is, the structural unit represented by
[R.sup.1.sub.2SiO.sub.2/2] (hereinafter sometimes referred to as
"bifunctional structural unit"), may include a structure of the
formula [1-2] where one of oxygen atoms bonded to a silicon atom of
the bifunctional structural unit constitutes a hydroxy group or an
alkoxy group.
[R.sup.1.sub.2SiXO.sub.1/2 ][1]
In the formula [1-2], X represents a hydroxy group or an alkoxy
group; and R.sup.1 has the same meaning as in the general formula
[1].
[0169] The bifunctional structural unit may contain a structural
moiety surrounded by a broken line of the formula [1-b] and further
contain a structural moiety surrounded by a broken line of the
formula [1-2-b]. In other words, a structural unit having not only
a group R.sup.1 but also a hydroxy group or an alkoxy group at a
terminal end thereof is included in the bifunctional structural
unit. More specifically, the hydroxyl- or alkoxy-containing
bifunctional structural unit contains the structural moiety
surrounded by the broken line of the formula [1-2-b] in the case
where an alkoxy group of the alkoxysilane compound as the raw
material of the component (A-1) remains or is substituted by a
hydroxy group or in the case where a chlorine atom of the
chlorosilane compound as the raw material of the component (A-1) is
substituted by a hydroxy group. In the formula [1-b], each oxygen
atom forms a siloxane bond Si--O--Si with adjacent silicon atoms.
One oxygen atom of the Si--O--Si bond is shared by the structural
unit of the formula [1-b] and the adjacent structural unit and thus
is expressed as "O.sub.1/2".
##STR00001##
In the formula [1-2-b], X represents a hydroxy group or an alkoxy
group. In the formulas [1-b] and [1-2-b], R.sup.1 has the same
meaning as in the general formula [1].
[0170] The structural unit of the polysiloxane compound [1] where m
is 1 and n is 3, that is, the structural unit represented by
[R.sup.1SiO.sub.3/2] (hereinafter sometimes referred to as
"trifunctional structural unit"), may include a structure of the
formula [1-3] or [1-4] where one or two of oxygen atoms bonded to a
silicon atom of the trifunctional structural unit constitutes a
hydroxy group or an alkoxy group.
[R.sup.1SiX.sub.2O.sub.1/2] [1-3]
[R.sup.1SiXO.sub.2/2] [1-4]
In the formulas [1-3] and [1-4], X represents a hydroxy group or an
alkoxy group. When there are a plurality of X in the formula [1-3],
X can be of the same kind or different kinds. In the formulas [1-3]
and [1-4], R.sup.1 has the same meaning as in the general formula
[1].
[0171] The trifunctional structural unit may contain a structural
moiety surrounded by a broken line of the formula [1-c] and further
contain a structural moiety surrounded by a broken line of the
formula [1-3-c] or [1-4-c]. In other words, a structural unit
having not only a group R.sup.1 but also either or both of a
hydroxy group and an alkoxy group at terminal ends thereof is
included in the trifunctional structural unit.
##STR00002##
In the formula [1-2-b], X represents a hydroxy group or an alkoxy
group. In the formulas [1-b] and [1-2-b], R.sup.1 has the same
meaning as in the general formula [1].
[0172] The polysiloxane compound [1] may have a plurality of
structural units represented by the general formula [1]. In this
case, the plurality of structural units can be of the same kind or
different kinds.
[0173] The polysiloxane compound [1] may have, in addition to the
structural unit of the general formula [1], a structural unit of
the general formula [2].
[SiO.sub.4/2] [2]
In the general formula [2], an oxygen atom of the structural unit
of the general formula [2] is a siloxane bond-forming oxygen atom
or a hydroxyl oxygen atom. The presence of the structural unit of
the general formula [1] and the structural unit of the general
formula [2] in the polysiloxane compound is advantageous in that
the resulting cured product can easily attain improved heat
resistance and good adhesion to various members. Hereinafter, the
polysiloxane compound having the structural unit of the general
formula [1] and the structural unit of the general formula [2] is
sometimes referred to as "polysiloxane compound [2]".
[0174] In the polysiloxane compound [2], there is no particular
limitation on the ratio between the structural unit of the general
formula [1] and the structural unit of the general formula [2]. It
is preferable that the ratio of
[SiO.sub.4/2]/[R.sup.1.sub.mSiO.sub.n/2] is lower than or equal to
1.0 or lower in order to facilitate controlling the mass-average
molecular weight of the polysiloxane compound to within a
preferable range.
Second Embodiment
[0175] The component (A-2) is a polysiloxane compound obtained by
hydrolysis and polycondensation of at least one kind of
alkoxysilane compound of the general formula [3] (hereinafter
sometimes referred to as "polysiloxane compound [3]").
(R.sup.1).sub.ySi(OR.sup.2).sub.4-y [3]
In the general formula [3], R.sup.1 has the same meaning as in the
general formula [1]; when there are a plurality of R.sup.1, R.sup.1
can be of the same kind or different kinds; R.sup.2 each
independently represents a C.sub.1-C.sub.4 linear alkyl group or a
C.sub.3-C.sub.4 branched alkyl group; when there are a plurality of
R.sup.2, R.sup.2 can be of the same kind or different kinds; and y
represents an integer of 1 to 3; and
[0176] Examples of the C.sub.1-C.sub.4 linear alkyl group or
C.sub.3-C.sub.4 branched alkyl group as R.sup.2 in the general
formula [3] include methyl, ethyl, propyl, butyl, isopropyl,
isobutyl and sec-butyl, tert-butyl. Among others, methyl and ethyl
are preferred
[0177] The alkoxysilane compound [3] is classified into a
trialkoxysilane compound (R.sup.1Si(OR.sup.2).sub.3), a
dialkoxysilane compound ((R.sup.1).sub.2Si(OR.sup.2).sub.2) and a
monoalkoxysilane compound ((R.sup.1).sub.3SiOR.sup.2) depending on
the number of Y in the structural unit of the general formula [3].
It is feasible to use one kind of the alkoxysilane compound alone
or two or more kinds of the alkoxysilane compounds in combination
at an arbitrary ratio.
[0178] Examples of the trialkoxysilane compound include, but are
not limited to, methyltrimethoxysilane, methyltriethoxysilane,
methyltripropoxysilane, methyltriisopropoxysilane,
ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane,
ethyltriisopropoxysilane, propyltrimethoxysilane,
propyltriethoxysilane, propyltripropoxysilane,
propyltriisopropoxysilane, isopropyltrimethoxysilane,
isopropyltriethoxysilane, isopropoxyltripropoxysilane,
isopropyltriisopropoxysilane, phenyltrimethoxysilane,
phenyltriethoxysilane, phenyltripropoxysilane,
phenyltriisopropoxysilane, trifluoromethyltrimethoxysilane,
trifluoromethyltriethoxysilane, pentafluoroethyltrimethoxysilane,
pentafluoroethyltriethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane,
3,3,3-trifluoropropyltriethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropyltriethoxysilane,
[2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane,
[2-(3,4-epoxycyclohexy)ethyl]triethoxysilane,
3-(methacryloyloxy)propyltrimethoxysilane,
3-(methacryloyloxy)propyltriethoxysilane, vinyltrimethoxysilane,
vinyltriethoxysilane, trimethoxysilane and triethoxysilane.
[0179] Among others, methyltrimethoxysilane, methyltriethoxysilane,
ethyltrimethoxysilane, ethyltriethoxysilane,
phenyltrimethoxysilane, phenyltriethoxysilane,
trifluoromethyltrimethoxysilane and trifluoromethyltriethoxysilane
are preferred. Particularly preferred are methyltrimethoxysilane,
methyltriethoxysilane, phenyltrimethoxysilane and
phenyltriethoxysilane.
[0180] Examples of the dialkoxysilane compound include, but are not
limited to, dimethyldimethoxysilane, dimethyldiethoxysilane,
dimethyldipropoxysilane, dimethyldiisopropoxysilane,
diethyldimethoxysilane, diethyldiethoxysilane,
diethyldipropoxysilane, diethyldiisopropoxysilane,
dipropyldimethoxysilane, dipropyldiethoxysilane,
diisopropyldimethoxysilane, diisopropyldiethoxysilane,
diphenyldimethoxysilane, diphenyldiethoxysilane,
diphenyldipropoxysilane, diphenyldiisopropoxysilane,
methylphenyldimethoxysilane, methylphenyldiethoxysilane,
bis(trifluoromethyl)dimethoxysilane,
bis(trifluoromethyl)diethoxysilane,
bis(3,3,3-trifluoropropyl)dimethoxysilane,
bis(3,3,3-trifluoropropyl)diethoxysilane,
methyl(3,3,3-trifluoropropyl)dimethoxysilane and
methyl(3,3,3-trifluoropropyl)diethoxysilane.
[0181] Among others, dimethyl dimethoxysilane, dimethyl
diethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane,
diphenyldimethoxysilane, diphenyldiethoxysilane,
methylphenyldimethoxysilane, methylphenyldiethoxysilane,
bis(trifluoromethyl)dimethoxysilane and
bis(trifluoromethyl)diethoxysilane. Particularly preferred are
dimethyldimethoxysilane and dimethyldiethoxysilane.
[0182] Examples of the monoalkoxysilane compound include, but are
not limited to, trimethylmethoxysilane, trimethylethoxysilane,
trimethylpropoxysilane, trimethylisopropoxysilane,
triethylmethoxysilane, triethylethoxysilane, triethylpropoxysilane,
triethylisopropoxysilane, triphenylmethoxysilane,
triphenylethoxysilane, triphenylpropoxysilane,
triphenylisopropoxysilane, tris(trifluoromethyl)methoxysilane and
tris(trifluoromethyl)ethoxysilane.
[0183] In the hydrolysis and polycondensation of the at least one
kind of alkoxysilane compound [3], at least one kind of
alkoxysilane compound of the general formula [4] (hereinafter
referred to as "alkoxysilane compound [4]") may be added.
Si(OR.sup.2).sub.4 [4]
In the general formula [4], R.sup.2 has the same meaning as in the
general formula [3]. The addition of the at least one kind of
alkoxysilane compound [4] is advantageous in that the cured product
can easily attain improved heat resistance and good adhesion to
various members.
[0184] Examples of the alkoxysilane compound [4] are
tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and
tetraisopropoxysilane.
[0185] A detail explanation will be given of the process for
hydrolysis and polycondensation of the at least one kind of
alkoxysilane compound [3]. First, the alkoxysilane compound [3] is
weighed by a predetermined amount and put into a reactor at room
temperature (i.e. atmospheric temperature without heating or
cooling in the range of generally about 15 to 30.degree. C.; the
same applies to the following). Then, water for hydrolysis of the
alkoxysilane compound, a catalyst for polycondensation of the
alkoxysilane compound and, optionally a reaction solvent, are put
into the reactor. The order of introduction of the reaction
materials into the reactor is not limited to the above. The
reaction materials can be introduced into the reactor in any
arbitrary order. In the case of using the alkoxysilane compound
[4], the alkoxysilane compound [4] can be put into the reactor in
the same manner as the alkoxysilane compound [3]. The resulting
reaction solution is subjected to hydrolysis and polycondensation
while stirring at a predetermined temperature for a predetermined
time. By this, the polysiloxane compound as the component (A-2) is
obtained. It is herein preferable to set the reactor as a closed
system, or to equip the reactor with a reflux device such as
condenser and reflux the reaction system, for the purpose of
preventing unreacted alkoxysilane raw material, water, reaction
solvent and/or catalyst from being distilled out of the reaction
system during the hydrolysis and polycondensation.
[0186] There is no particular limitation on the amount of water
used in the preparation of the component (A-2). In view of the
reaction efficiency, the amount of the water used is preferably 1
to 5 times in terms of the ratio of the mole number of water to the
total mole number of alkoxy group in the alkoxysilane compound as
the raw material. When the mole number ratio of water is 1.0 time
or higher, it is likely that hydrolysis of the alkoxysilane
compound will proceed efficiently. When the mole number ratio of
water is 5 times or lower, it is less likely that the alkoxysilane
compound will be difficult to handle due to gelation.
[0187] In the preparation of the component (A-2), it is feasible to
use the reaction solvent although the reaction can be performed in
the presence of no solvent. There is no particular limitation on
the kind of the reaction solvent as long as the reaction solvent
does not interfere with the reaction for synthesis of the component
(A-2). Among others, a water-soluble organic solvent is preferred
as the reaction solvent. Particularly preferred is an alcohol
solvent because the reaction proceeds at an appropriate reaction
rate in the presence of the alcohol solvent. Examples of the
alcohol solvent include, but are not limited to, methanol, ethanol,
1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butylalcohol,
propylene glycol monomethylether, propylene glycol monoethylether,
propylene glycol mono-n-propylether, propylene glycol
mono-n-butylether, propylene glycol mono-t-butylether,
3-methoxy-1-butanol and 3-methyl-3-methoxy-1-butanol. The amount of
the reaction solvent used is preferably 1.0 time or less in terms
of the mole ratio of the reaction solvent to the water used.
[0188] The condensation can be performed without the use of the
reaction solvent as mentioned above. In this case, alcohol
generated by hydrolysis of the alkoxysilane compound plays a role
of the reaction solvent.
[0189] In the preparation of the component (A-2), the catalyst can
be an acid catalyst, a base catalyst or a metal complex catalyst.
An acid catalyst is preferred for ease of control of the total
amount of silanol and/or alkoxysilyl group in the component (A-2).
There is no particular limitation on the kind of the acid catalyst.
Examples of the acid catalyst includes acetic acid, propionic acid,
trifluoroacetic acid, methanesulfonic acid,
trifluoromethanesulfonic acid, formic acid, oxalic acid, maleic
acid, camphorsulfonic acid, benzenesulfonic acid, tosic acid,
hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and
boric acid. Among others, acetic acid, hydrochloric acid, sulfuric
acid and nitric acid are preferred for ease of removal of the
catalyst after the completion of the reaction. Particularly
preferred is acetic acid. There is no particular limitation on the
kind of the base catalyst. Examples of the base catalyst include
1,8-diazabicyclo[5.4.0]undec-7-ene, diethylamine, triethylamine,
imidazole, pyridine, triphenylphosphine, sodium hydroxide,
potassium hydroxide, lithium hydroxide, magnesium hydroxide, sodium
carbonate, potassium carbonate, cesium carbonate and sodium
hydrocarbonate. There is no particular limitation on the kind of
the metal complex catalyst. Examples of the metal complex catalyst
include zinc octoate, zinc benzoate, zinc p-tert-butylbenzoate,
zinc laurate, zinc stearate, aluminum chloride, aluminum
perchlorate, aluminum phosphate, aluminum triisopropoxide, aluminum
acetylacetonate, aluminum butoxybisethylacetoacetate, tetrabutyl
titanate, tetraisopropyl titanate, tin octoate, tin naphthenate and
cobalt naphthenate.
[0190] The amount of the catalyst used in the preparation of the
component (A-2) is preferably 1.0.times.10.sup.-5 to
1.0.times.10.sup.-1 times in terms of the ratio of the mole number
of the catalyst to the total mole number of alkoxy group in the
alkoxysilane compound as the raw material.
[0191] In the preparation of the component (A-2), the reaction time
is varied depending on the kind of the catalyst and is generally in
the range of about 3 to 48 hours. The reaction time is generally in
the range of room temperature to 180.degree. C.
[0192] After the reaction, it is preferable to separate and purify
the component (A-2) from the reaction system in view of the
handling of the component (A-2). There is no particular limitation
on the process of separation of the component (A-2). For example,
it is feasible to separate the component (A-2) from the reaction
system by extraction and, more specifically, by, after the
reaction, cooling the reaction solution down to room temperature
and bringing the reaction solution into contact with a nonaqueous
organic solvent as an extraction solvent. After the extraction, the
solution may be washed with water or a sodium chloride solution and
dehydrated with a drying agent as needed. The high purity component
(A-2) or solution thereof is obtained by finally removing a
volatile component under reduced pressure from the solution. In the
case where, after the reaction, the reaction solution is separated
into an aqueous layer and a product layer containing the component
(A-2) at room temperature, it is feasible to remove the aqueous
layer without using the extraction solvent and then purify the
component (A-2) from the product layer.
[0193] Examples of the nonaqueous organic solvent used as the
extraction solvent include: ether solvents such as diethyl ether,
diisopropyl ether, methyl t-butyl ether and dibutyl ether; aromatic
solvents such as benzene, toluene and xylene; ester solvents such
as ethyl acetate and butyl acetate; chlorinated solvents such as
chloroform and dichloromethane; aliphatic solvents such as pentane,
hexane, heptane and cyclohexane; alcohol solvents such as 1-butanol
and isobutyl alcohol; and ketone solvents such as methyl isobutyl
ketone. These solvents can be used solely or as a mixture of two or
more thereof at an arbitrary ratio.
[0194] There is no particular limitation on the kind of the drying
agent. Examples of the drying agent include solid drying agents
such as magnesium sulfate, sodium sulfate, calcium sulfate and
synthetic zeolite.
[0195] There is no particular limitation on the mass-average
molecular weight of the component (A). In general, it suffices that
the mass-average molecular weight of the component (A) is 200 to
50000. The mass-average molecular weight of the component (A) is
preferably 300 to 10000, more preferably 600 to 3000, in order to
secure sufficient flowability for good mixing of the component (A)
with the component (B). Herein, the mass-average molecular weight
refers to a value determined by gel permeation chromatography (GPC)
on the basis of a calibration curve using polystyrene as a standard
material.
[0196] There is no particular limitation on the total amount of
silanol and alkoxysilyl groups in the component (A). The total
amount of silanol and alkoxysilyl groups in the component (A) is
preferably in the range of 1 to 15 mmol/g, more preferably 3 to 15
mmol/g. When the total amount of silanol and alkoxysilyl groups in
the component (A) is in the above specific range, it is possible to
allow smooth curing of the curable resin composition while
particularly suppressing the occurrence of foaming in the cured
product. Further, it is possible to ensure good dispersibility of
the component (B) in the curable resin composition and, in the case
of adding an inorganic filler to the curable resin composition,
good dispersibility of the inorganic filler in the curable resin
composition so that the curable resin composition is able to
maintain good dispersion stability for a long time when the total
amount of silanol and alkoxysilyl groups in the component (A) is in
the above specific range. Furthermore, the cured product of the
curable resin composition is able to show good adhesion to various
members when the total amount of silanol and alkoxysilyl groups in
the component (A) is in the above specific range. Herein, the total
amount of silanol and alkoxysilyl groups in the component (A) is
determined by measuring a .sup.29Si-NMR spectrum of the component
(A) and calculating a ratio between the peak area of Si bonded to
OH and OR groups and the peak area of Si not bonded to OH and OR
groups.
[0197] <Synthesis or Availability of Component (A)>
[0198] There is no particular limitation on the process for
synthesis or availability of the component (A). One example of the
preparation of the polysiloxane compound as the component (A-1) is
to perform hydrolysis and polycondensation of at least one kind
selected from the group consisting of alkoxysilane compounds and
chlorosilane compounds. For instance, the alkoxysilane compound may
be reacted in the presence of water and catalyst for the hydrolysis
and polycondensation of the alkoxysilane compound. Further, a
chlorosilane compound may be hydrolyzed and used.
[0199] As one example of the polysiloxane compound as the component
(A-1), it is feasible to prepare the polysiloxane compound [3] by
hydrolysis and polycondensation of at least one kind of
alkoxysilane compound [3]. At least one kind of alkoxysilane
compound [4] may be used in combination with the alkoxysilane
compound [3] during the hydrolysis and polycondensation.
[0200] The hydrolysis and polycondensation of at least one kind of
alkoxysilane compound [3] and the hydrolysis and polycondensation
of at least one kind of alkoxysilane compound [3] and at least one
kind of alkoxysilane compound [4] can be performed according to the
above-mentioned process for preparation of the polysiloxane
compound as the component (A-2).
[0201] <Component (B): Silica>
[0202] The component (B) is a silica whose extract water has a pH
of 6.1 or lower, preferably 4.0 to 6.1, at 25.degree. C. In the
present invention, it is possible by the addition of the component
(B) to smoothly discharge gas generated during thermal curing of
the curable resin composition and prevent foaming in the cured
product although the condensation type polysiloxane compound is
used as the component (A) in the curable resin composition.
[0203] In the present invention, the extract water of the component
(B) refers to an extract obtained by stirring 10 g of the component
(B) as a sample in 200 ml of purified water at 80.+-.3.degree. C.
for 1 hour and cooling the resulting liquid to room temperature.
The pH of the extract water refers to a value determined by the
following method.
[0204] The pH of the extract water of the component (B) is
determined according to the test method as specified in JIS K 1150:
1994. More specifically, the component (B) is dried for 2 hours in
the air at about 170.degree. C. or under vacuum at about
150.degree. C. and then weighed by an amount of about 10 g to the
second decimal place. This component (B) is put into a 300-mL
beaker, followed by adding 200 ml of purified water into the beaker
and covering the beaker by a watch glass. The resulting liquid is
stirred at 80.+-.3.degree. C. for 1 hour and cooled down to room
temperature. The supernatant liquid is recovered as the extract
water. After the temperature of the supernatant liquid is set to
25.degree. C., the pH of the supernatant liquid is measured with a
pH meter. Herein, the pH value is read to the first decimal place.
The purified water used is of 1.times.10.sup.-3 S/m or lower
electric conductivity. The pH meter used is of the model II as
specified in JIS Z 8802. The beaker used is of the hard type as
specified in JIS R 3505.
[0205] As the component (B), there can be used crystalline silica,
natural fused silica, synthetic fused silica, deflagration silica,
fumed silica, sol-gel silica, flame fused silica and precipitated
silica. These silica materials can be used solely or as a mixture
of two or more thereof at an arbitrary ratio. Among others, natural
fused silica, synthetic fused silica and deflagration silica are
preferred in view of the fact that these silica materials have good
flowability at room temperature or under heating, i.e., good
formability. It is feasible to use natural fused silica, synthetic
fused silica or deflagration silica in combination with any other
kind of silica at an arbitrary ratio. Examples of the preferable
silica combination include, but are not limited to, a combination
of natural fused silica and deflagration silica and a combination
of synthetic fused silica and deflagration silica.
[0206] The natural fused silica is a generic term for spherical
silica particles prepared by fusing natural silica rock and is
manufactured as, for example, FB-series silica by Denka Company
Limited., Fuselex-series silica, MSV-series silica and MSR-series
silica by Tatsumori Ltd., HS-series silica by Nippon Steel &
Sumikin Materials Co., Ltd. etc.
[0207] Specific examples of the FB-series silica of Denka Company
Limited. include those available under the trade names of, but are
not limited to, FB-5D, FB-12D, FB-20D, FB-105, FB-940, FB-9454,
FB-950, FB-105FC, FB-870FC, FB-875FC, FB-9454FC, FB-950FC,
FB-300FC, FB-105FD, FB-970FD, FB-975FD, FB-950FD, FB-300FD,
FB-400FD, FB-7SDC, FB-5SDC, FB-3SDC, FB-405, FB-570 and FB-820.
[0208] Specific examples of the MSR-series silica of Tatsumori Ltd.
include those available under the trade names of, but are not
limited to, MSR-LV24 and MSR-5100.
[0209] The synthetic fused silica is a generic term for spherical
silica particles prepared by e.g. fusing silicon tetrachloride and
is manufactured as, for example, Exceria-series silica by Tokuyama
Corporation, EMIX-series silica by Tatsumori Ltd. etc.
[0210] Specific examples of the Exceria-series silica of Tokuyama
Corporation include those available under the trade names of, but
are not limited to, SE-8, SE-15, SE-30, SE-40, SE-15K, SE-30K,
UF-305, UF-310, UF-320, UF-345, UF-725 and ML-902SK.
[0211] Specific examples of the EMIX-series silica of Tatsumori
Ltd. include those available under the trade names of, but are not
limited to, EMIX-CER.
[0212] The deflagration silica is a generic term for spherical
silica particles prepared by oxidation of silicon powder and is
manufactured as, for example, Admafine-series silica by Admatechs.,
XR-series silica by Tatsumori Ltd. etc.
[0213] Specific examples of the Admafine-series silica of
Admatechs. include those available under the trade names of, but
are not limited to, SO-C1, SO-C2, SO-C4, SO-C5 and SO-C.
[0214] Specific examples of the XR-series silica of Tatsumori Ltd.
etc. include those available under the trade names of, but are not
limited to, XR-08P and XR-15P.
[0215] There is no particular limitation on the particle shape of
the component (B). As the component (B), the silica can have a
crushed shape, spherical shape, sheet-like shape, beads-like shape
or the like. Among others, spherical silica is preferred in view of
the formability of the curable resin composition. It is feasible to
use, as the component (B), spherical silica in combination with any
other type of silica at an arbitrary ratio.
[0216] As to the particle size distribution of the component (B),
the median particle size of the silica is preferably in the range
of 0.02 to 500 .mu.m, more preferably 0.05 to 100 .mu.m, as
determined by a laser diffraction particle size distribution
analysis method. The maximum particle size of the component (B) is
preferably 750 .mu.m or smaller, more preferably 150 .mu.m or
smaller. The minimum particle size of the component (B) is not
particularly limited. Herein, the particle size of the component
(B) is measured with a laser diffraction particle size distribution
analyzer. There is no particular limitation on the type of the
laser diffraction particle size distribution analyzer used.
Examples of the laser diffraction particle size distribution
analyzer are Microtrac manufactured by Nikkiso Co., Ltd., LA
manufactured by Horiba Ltd., CILAS manufactured by CILAS Co., Ltd.,
Mastersizer manufactured by Malvern Instruments Ltd. and LS
manufactured by Beckman Coulter Inc. In laser diffraction particle
size distribution analysis, the median size, also called d50,
refers to a particle size at which particles are divided into two
equal parts by volume.
[0217] In general, the particle size of the natural fused silica
and the particle size of the synthetic fused silica are in the
range of 1 to 100 .mu.m; and the particle size of the deflagration
silica is in the range of 0.1 to 3 .mu.m.
[0218] The smaller the particle size of the component (B), the
larger the specific surface of the component (B), the larger the
amount of silanol group present at the surface of the component per
unit volume. There is a tendency that the effect of suppressing
foaming in the cured product increases with increase in the amount
of silanol group present at the surface of the component per unit
volume so that it is possible to obtain the cured product without
foaming even when the amount of the component (B) relative to the
total amount of the components (A) and (B) is small. On the other
hand, there is a tendency that the formability of the curable resin
composition becomes lower as the flowability of the curable resin
composition at room temperature or under heating deteriorates with
decrease in the particle size of the component (B). For these
reasons, it is preferable that the particle size of the component
(B) is in the above specific range.
[0219] The silica contained as the component (B) may show a
plurality of frequency peaks in particle size distribution
analysis. In the case of forming the curable resin composition by
transfer molding process, the component (B) is preferably a mixture
of particles of different large sizes at a ratio convenient for
closest packing (hereinafter referred to as "closest packing
component (B)"). For example, it is feasible to prepare the
component (B) by mixing large size particles with middle size
particles, small size particles or both thereof at a given ratio
such that the component (B) has a closest packing structure in
which the spaces between the large size particles are filled with
the middle size particles, small size particles or both thereof. By
the use of the closest packing component (B), it is possible to
significantly improve the flowability of the curable resin
composition under heating and facilitate forming of the curable
resin composition by transfer molding process. It is also possible
by the use of the closest packing component (B) to increase the
packing rate of the cured product and improve the mechanical
strength and electrical properties of the cured product. The
particle size distribution of the closest packing component (B) may
show two frequency peaks in total, one in the range of 10 to 100
.mu.m and the other in the range of 1 to 10 .mu.m, or show three
frequency peaks in total, one in the range of 10 to 100 .mu.m, the
other in the range of 1 to 10 .mu.m and the still other in the
range of 0.1 to 1 .mu.m, as determined by a laser diffraction
particle size distribution analysis method.
[0220] Specific examples of the closest packing component (B)
include, but are not limited to, those manufactured under the trade
names of FB-940, FB-570 and FB-820 by Denka Company Limited,
Exceria ML-902SK by Tokuyama Corporation, MSR-LV24, MSR-5100 and
EMIX-CER by Tatsumori Ltd. and the like. The closest packing
component (B) may be prepared by mixing two or more different kinds
of components (B).
[0221] Further, the component (B) may include particles having a
particle size of 3 .mu.m or smaller (hereinafter referred to as
"fine particle-containing component (B)". By the use of the fine
particle-containing component (B), it is possible to promote the
condensation reaction of silanol and alkoxysilyl groups in the
component during heating of the curable resin composition and
thereby possible to significantly increase the curing speed of the
curable resin composition. The use of such a fine
particle-containing component is particularly effective in the case
of forming the curable resin composition by transfer molding
process. In this case, it is possible to obtain various effects
such as lower forming temperature, shorter forming time and
improved mold releasability and improve the productivity and
surface smoothness of the cured product.
[0222] The amount of the particles of 3 .mu.m or smaller particle
size in the fine particle-containing component (B) is preferably in
the range of 1 to 50 mass %, more preferably 12 to 45 mass %. When
the amount of the particles of 3 .mu.m or smaller particle size in
the fine particle-containing component (B) is less than 1 mass %,
the above curing speed increasing effect may not be obtained. When
the amount of the particles of 3 .mu.m or smaller particle size in
the fine particle-containing component (B) exceeds 50 mass %, the
flowability and formability of the curable resin composition may be
deteriorated.
[0223] There is no particular limitation on the kind of the
particles of 3 .mu.m or smaller particle size in the fine
particle-containing component (B). As such fine silica particles,
deflagration silica, fumed silica, sol-gel silica and flame fused
silica are usable. Among others, deflagration silica is preferred
in view of the fact that this silica material has good flowability
at room temperature or under heating, i.e., good formability.
Examples of the deflagration silica include those manufactured as
Admafine SO-series by Admatechs., XR-series by Tatsumori Ltd. and
the like.
[0224] In the case of forming the curable resin composition by
transfer molding process, it is preferable that the component (B)
is the closest packing component (B) and, at the same time, the
fine particle-containing component (B). It is possible by the use
of such a component (B) to not only improve the flowability of the
curable resin composition under heating but also increase the
curing speed of the curable resin composition. Examples of the
closest packing/fine particle-containing component (B) include, but
are not limited to, those prepared by mixing Tokuyama Corporation's
silica Exceria ML-902SK and Admatechs silica Admafine SO-series
such that the amount of the Admafine SO-series relative to the
total amount of the Exceria ML-902SK silica and the Admafine
SO-series ranges from 1 to 50 mass %.
[0225] It is preferable that silanol group remain exposed at the
surface of the component (B) without chemically modifying the
surface of the component (B) by a coupling agent etc. As a matter
of course, chemically modified silica can be used as the component
(B) unless the effects of the present invention are impaired.
[0226] In the present invention, the component (B) is used such
that the amount of the component (B) relative to the total amount
of the components (A) and (B) is in the range of 70 to 97 mass %.
When the amount of the component (B) is less than 70 mass %, there
may occur foaming in the cured product. When the amount of the
component (B) exceeds 97 mass %, it becomes difficult to obtain the
cured product of bulk shape. When the amount of the component (B)
is in the range of 70 to 97 mass %, it is possible to obtain the
cured product of bulk shape or film shape while suppressing the
occurrence of foaming in the cured product.
Other Component
[0227] For the purpose of adjusting the physical properties of the
cured product, an additive component such as inorganic filler,
heat-resistant resin, mold release agent, pigment, flame retardant,
curing catalyst and anti-blocking agent may be contained in
addition to the components (A) and (B). These additives can be used
solely or as a mixture of two or more thereof as an arbitrary
ratio. There is no particular limitation on the amount of the
additive component as long as the additives are used in effective
amounts within the range that does not impair the foaming
suppression characteristics of the cured product. The sum of the
amounts of the respective additives is preferably 5 mass % or less
based on the total amount of the components (A) and (B).
[0228] Examples of the inorganic filler include silica different
from the silica contained as the component (B), alumina, titania,
zirconia, clay mineral e.g. talc or kaolin, glass, zinc oxide,
boron nitride, aluminum nitride, calcium carbonate, magnesium
carbonate, zirconium phosphate, zirconium phosphate tungstate and
carbon isotope e.g. diamond or carbon nanotube. These inorganic
fillers can be used solely or in combination of two or more kinds
thereof. There is no particular limitation on the shape of the
inorganic filler. The inorganic filler can have a crushed shape,
spherical shape, sheet-like shape, beads-like shape, rod-like
shape, fibrous shape, acicular shape, hollow shape or the like.
[0229] Examples of the heat-resistant resin include nanocellulose,
aramid fiber, carbon fiber, PEEK resin and polyimide. These
heat-resistant resins can be used solely or in combination of two
or more kinds thereof. There is no particular limitation on the
shape of the heat-resistant resin. The heat-resistant resin can
have a crushed shape, spherical shape, sheet-like shape, beads-like
shape, rod-like shape, fibrous shape, acicular shape, hollow shape
or the like.
[0230] Examples of the mold release agent include Candellia wax,
Carnauba wax, Rice wax, Montana wax, paraffin wax, synthetic wax,
tetrafluoroethylene resin,
tetrafluoroethylene-perfluoroalkoxyethyelene copolymer resin,
tetrafluoroethylene-hexafluoropropylene copolymer resin,
tetrafluoroethylene-ethylene copolymer resin, vinylidene fluoride
resin, dimethylsilicone and fluorosilicone. These mold release
agents can be used solely or in combination of two or more kinds
thereof.
[0231] Examples of the pigment include carbon black, hydrozincite,
white lead, lithopone, titanium dioxide, precipitated barium
sulfate, barite powder, red lead, red iron oxide, chrome yellow,
ultramarine blue, zinc yellow, prussian blue, phthalocyanine,
polycyclic pigment and azo pigment. These pigments can be used
solely or in combination of two or more kinds thereof.
[0232] Examples of the flame retardant include a halogen flame
retardant, a phosphorus flame retardant, a metal hydroxide flame
retardant and an antimony flame retardant. These flame retardants
can be used solely or in combination of two or more kinds
thereof
[0233] Examples of the curing catalyst include the same as those
used in the preparation of the component (A). It is possible to
adjust the curing speed of the curable resin composition by
addition of the curing catalyst.
[0234] The anti-blocking agent may be contained in the curable
resin composition in order to, when the curable resin composition
is tableted, prevent adhesion or integration of the tablets and
maintain the tablets at a constant shape. Examples of the
anti-blocking agent include lauric acid, myristic acid, palmitic
acid, margaric acid, stearic acid, arachidic acid, behenic acid, Li
salt of stearic acid, Na salt of stearic acid, Mg salt of stearic
acid, K salt of stearic acid, Ca salt of stearic acid, Ba salt of
stearic acid, Al salt of stearic acid, Zn salt of stearic acid, Fe
salt of stearic acid, Ca salt of lauric acid, Ba salt of lauric
acid, Zn salt of lauric acid, Ca salt of behenic acid, Ba salt of
behenic acid, Zn salt of behenic acid, Ca salt of 12-hydroxystearic
acid, Mg salt of 12-hydroxystearic acid, Zn salt of
12-hydroxystearic acid, aluminum silicate, crystalline silica,
natural fused silica, synthetic fused silica, deflagration silica,
fumed silica, sol-gel silica, flame fused silica, precipitated
silica, zeolite, clay mineral e.g. talc or kaolin, diatomite,
polyethylene beads, polytetrafluoroethylene, polymethyl
methacrylate, acrylic resin and silicon resin. These anti-blocking
agents can be used solely or in combination of two or more kinds
thereof.
[0235] For the purpose of adjusting the dispersibility of the
additive component such as inorganic filler, heat-resistant resin,
mold release agent, pigment, flame retardant, curing catalyst and
anti-blocking agent, a coupling agent may be additionally contained
in the curable resin composition. Examples of the coupling agent
include methyltrimethoxysilane, methyltriethoxysilane,
phenyltrimethoxysilane, phenyltriethoxysilane,
ethyltrimethoxysilane, propyltrimethoxysilane,
isopropyltrimethoxysilane, trifluoromethyltrimethoxysilane,
pentafluoromethyltrimethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane, vinyltrimethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-methacryloxypropyltrimethoxysilane,
3-aminopropyltrimethoxysilane,
tris(trimethoxysilylpropyl)isocyanurate and
3-isocyanatepropyltriethoxysilane. As long as the coupling agent is
contained in an effective amount within the range that does not
impair the foaming suppression characteristics of the cured
product, there is no particular limitation on the amount of the
coupling agent. The amount of the coupling agent is preferably 2
mass % or less based on the total amount of the components (A) and
(B).
[0236] <Preparation of Curable Resin Composition>
[0237] The curable resin composition of the present invention is
prepared by mixing the component (A), the component (B) and,
optionally, the additive component. The mixing amounts of the
respective components are as mentioned above. It is preferable to
uniformly disperse the respective components and, more
specifically, at least disperse the component (B) without
aggregation in the component (A). By ensuring good dispersibility
of the component (B) in the component (A), it is possible for the
cured product of the curable resin composition to attain good
adhesion and mechanical strength.
[0238] There is no particular limitation on the process for uniform
dispersion of the respective components. In general, the respective
components are uniformly dispersed by kneading the respective
components together at room temperature or under heating. There is
also no particular limitation on the order of introduction of the
respective components. It is feasible to introduce all the
components into a kneading container and then knead the components
in the kneading container. It is alternatively feasible to
introduce the respective components in any arbitrary order into the
kneading container and gradually knead the components in the
kneading container. In the case of using two or more different
kinds of components (A) and/or two or more different kinds of
components (B), these component ingredients may be mixed together
and then introduced into the kneading container or may be
separately introduced into the kneading container. As means of
kneading two or more kinds of components (A), there can be used a
mixing machine such as magnetic stirrer, mechanical stirrer, mixer,
planetary mixer, agitation defoaming device, static mixer,
double-arm kneader or pressure kneader. As means of kneading two or
more kinds of components (B), there can be used a mixing machine
such as mechanical stirrer, mixer, planetary mixer, Spartan mixer,
agitation defoaming device, high-speed fluidizing mixing device,
container rotary mixing device, V-type mixing device, W-type mixing
device, double-arm kneader or pressure kneader.
[0239] One example of the preparation of the curable resin
composition is to, in the case of using two or more kinds of
components (B), previously mix two or more kinds of components (B)
and knead at least the components (A) and (B). By the use of the
previously-mixed component (B), it is possible to efficiently
obtain the cured product with good formability. The reason for this
is assumed that, although there may occur aggregation between the
particles of the component (B) depending on the kinds, shapes and
sizes of the particles of the component (B), the occurrence of such
particle aggregation is suppressed by previously mixing the
particles of the component (B).
[0240] Another example of the preparation of the curable resin
composition is to, in the case of using two or more kinds of
components (B), knead one or more kinds of components (B) with the
component (A) and then knead another one or more kinds of component
(B) with the resulting kneaded composition.
[0241] Still another example of the preparation of the curable
resin composition is to, in the case of using three or more kinds
of components (B), previously mix two or more kinds of components
(B), knead the previously-mixed component (B) with the component
(B) and then knead another one or more kinds of components (B) with
the resulting kneaded composition.
[0242] There is no particular limitation on the process of kneading
of the respective components for the preparation of the curable
resin composition. It is feasible to knead the respective
components by manual means using a spatula, mortar or the like or
by means of a kneading machine. As the kneading machine, there can
be used a grinding device, two roll mill, three roll mill, Kneadex,
high-speed fluidizing mixing device, planetary mixer, double-arm
kneader, pressure kneader, continuous kneader or the like. In order
to prepare the curable resin composition with very good
dispersibility of the respective components, it is preferable to
knead the respective components by means of a double-arm kneader,
pressure kneader or continuous kneader.
[0243] In the case of kneading the respective components by the
kneading machine for the preparation of the curable resin
composition, the kneading temperature is preferably in the range of
room temperature to 250.degree. C. The kneading time is not
particularly limited. The respective components may be kneaded
under reduced pressure or with the flow of inert gas.
[0244] It is feasible to prepare the curable resin composition by,
in advance of kneading the respective components, subjecting the
respective components to so-called prekneading as pretreatment for
uniformizing the components to a certain degree by a mixing
machine. As the mixing machine for prekneading, there can be used a
mechanical stirrer, mixer, planetary mixer, high-speed fluidizing
mixing device, agitation defoaming device, grinding device or the
like. The whole or part of the components can be subjected to
prekneading. As a matter of course, the curable resin composition
may be prepared by kneading without prekneading.
[0245] The curable resin composition may be subjected to heat
treatment for partial condensation of the component (A)
(hereinafter referred to as "B-staging") in the resin composition.
By the B-staging, it is possible to adjust the flowability of the
curable resin composition at room temperature or under heating in
accordance with the forming process while increasing the curing
speed of the curable resin composition. It is particularly
preferable to perform the B-staging in the case of forming the
resin composition by transfer molding process. The curable resin
composition can be B-staged by, after kneading the respective
components, leaving the resulting kneaded composition still in an
oven of given temperature. Alternatively, the curable resin
composition can be B-staged while kneading the respective
components. It is alternatively feasible to obtain the B-staged
curable resin composition by subjecting the component (A) to heat
treatment and then kneading the component (A) with the other
component.
[0246] In the B-staging of the curable resin composition, the
heating time is preferably in the range of 50 to 250.degree. C.
There is no particular limitation on the heating time in the
B-staging of the curable resin composition. The B-staging may be
performed under reduced pressure or with the flow of inert gas.
[0247] [Tableting of Curable Resin Composition]
[0248] The curable resin composition of the present invention may
be tableted for use in various forming processes. There is no
particular limitation on the process of forming of the curable
resin composition. The curable resin composition can be formed by
cast molding process, dip forming process, drop forming process,
compression molding process, transfer molding process, injection
molding process or the like. In the case of forming the curable
resin composition by compression molding process, transfer molding
process or injection molding process, the curable resin
composition, when in paste or clay-like form, may be adhered,
integrated or deformed, without being maintained at a constant
shape, and thereby become difficult to measure, transfer and feed
into a molding machine. The curable resin composition, when in
tablet form, is easy to measure, transfer and feed into a molding
machine so that it is possible to automatize measurement, transfer
and feeding of the curable resin composition for significant
improvement of productivity. In particular, the curable resin
composition is preferably in tablet form in the case of forming the
curable resin composition by transfer molding process. The term
"tablet" as used herein means a solid capable of maintaining a
constant shape at room temperature with substantially no secular
change in shape.
[0249] There is no particular limitation on the shape of the
tableted product of the curable resin composition. The tableted
product can have a cylindrical column shape, rectangular column
shape, circular disc shape, spherical shape, ring shape or the
like.
[0250] There is no particular limitation on the process for
tableting of the resin composition. It is feasible to process the
resin composition into tablets by means of a mold and a press
machine, by means of a tableting machine with a mortar and pestle
jigs, or by extruding the resin composition into a strand through
an extruding machine and cutting the strand at equal intervals. As
the tableting machine, there can be used a hydraulic tableting
machine, serve motor-type tableting machine, rotary tableting
machine or the like. As the extruding machine, there can be used a
plunger extruder, uniaxial extruder, biaxial extruder, biaxial
uniaxial extruder or the like.
[0251] In the case of tableting the curable resin composition by
means of the mold and the press machine or by means of the
tableting machine, it is preferable to pulverize the curable resin
composition to a particle size of 10 mm or smaller or to preform
the curable resin composition into a rectangular column shape,
cylindrical column shape, crushed shape, spherical shape, acicular
shape etc. of 15 mm or smaller on one side. The curable resin
composition can be pulverized to a particle size of 10 mm or
smaller by manual means using a mortar or the like or by means of a
pulverizer such as hammer mill, cutter mill or freezing pulverizer.
The curable resin composition can be preformed into a rectangular
column shape, cylindrical column shape, crushed shape, spherical
shape, acicular shape etc. of 15 mm or smaller on one side by means
of an extruding machine such as plunger extruder, uniaxial
extruder, biaxial extruder, biaxial uniaxial extruder or the
like.
[0252] There is no particular limitation on the process of
containing the anti-blocking agent in the tableted product of the
curable resin composition. It is feasible to add the anti-blocking
agent simultaneously with the mixing of the components (A) and (B)
and the other additive or to add the anti-blocking agent during or
immediately after the pulverization or preforming of the curable
resin composition. By the addition of the anti-blocking agent, it
is possible to improve the flowability of the pulverized or
preformed product of the curable resin composition and improve the
workability of the resin composition during the tableting by the
mold and the press machine or by the tableting machine.
[0253] [Cured Product]
[0254] According to the present invention, there is provided a
cured product of the above curable resin composition. Even though
the condensation polymerizable polysiloxane compound is used as the
component (A) in the curable resin composition, it is possible to
obtain the cured product in various shapes and sizes without
causing foaming during curing. The cured product of the present
invention is able to show very high heat resistance as the
crosslinking structure of the cured product is constituted only by
chemically stable siloxane bond. There occur substantially no
deteriorations in the weight and mechanical strength of the cured
product of the present invention even when exposed to
high-temperature conditions of about 250.degree. C. for a
predetermined time. Further, the cured product of the present
invention is able to show good adhesion to various members as
either or both of silanol and alkoxysilyl groups remain in parts of
the cured product.
[0255] The cured product of the present invention is suitably
usable as an encapsulant for a semiconductor element. Since there
occurs no foaming in the cured product even when formed in various
sizes, the cured product is particularly suitably applicable as an
encapsulant for a semiconductor where large encapsulant thickness
and area are required. The encapsulant thickness is preferably 1 mm
or greater, more preferably 2 mm or greater, still more preferably
4 mm or greater. As a matter of course, the cured product is
applicable as an encapsulant for a semiconductor where an
encapsulant thickness smaller than the above value is required. The
upper limit of the encapsulant is not particularly limited. For
example, the encapsulant thickness can be set to 100 mm or smaller,
especially 20 mm or smaller. The cured product is suitable for use
as an encapsulant for a power semiconductor element because of its
very high heat resistance.
[0256] The cured product of the present invention is obtained by
curing the above curable resin composition.
[0257] There is no particular limitation on the curing temperature
as long as the curing reaction of the curable resin composition
proceeds. It is feasible to cure the resin composition by heating
at a constant temperature or by changing the curing temperature in
multiple stages or continuously as needed. The lower limit of the
curing temperature is not particularly limited but is preferably
150.degree. C. or higher. The upper limit of the curing temperature
is not particularly limited but is preferably 250.degree. C. or
lower. The curing time can be set to various times. The curing
pressure can be set to various pressures as needed. It is feasible
to cure the resin composition by heating at ordinary pressure,
under pressurized conditions or under reduced conditions.
[0258] The cured product may be obtained by subjecting the curable
resin composition to forming. There is no particular limitation on
the process of forming of the curable resin composition. It is
feasible to form the curable resin composition by cast molding
process, dip forming process, drop forming process, compression
molding process, transfer molding process, injection molding
process or the like. Among others, cast molding process,
compression molding process and transfer molding process are
preferred for ease of forming.
[0259] The cured product may be obtained by tableting the curable
resin composition and subjecting the tableted product of the
curable resin composition to forming.
[0260] In one embodiment of the present invention, the cured
product is obtained by feeding the curable resin composition to a
forming die, forming the curable resin composition in the forming
die, and then, heating and curing the curable resin composition in
the present invention. As in the case of the above-mentioned curing
temperature and pressure, the temperature and pressure during the
feeding and forming can be set to various temperatures. The heating
may be performed simultaneously with the forming. In this case, it
is feasible to obtain the cured product by taking the formed
product out of the forming die in a state where the curing reaction
of the resin composition has proceeded halfway, and then,
completely curing the product through additional heat treatment
(hereinafter sometimes referred to as "post curing").
[0261] One example of the production of the cured product by cast
molding process is to feed the curable resin composition into a
mold of given shape and material in a temperature range of room
temperature to below 150.degree. C., and then, cure the curable
resin composition in the casing mold by heating. There is no
particular limitation on the means of feeding the curable resin
composition. The curable resin composition can be dipped up and fed
by means of a tool such as spatula or can be fed by means of a
feeding machine such as dispenser.
[0262] One example of the production of the cured product by
compression molding process is to arrange the curable resin
composition between compressing mold members of given shape and
material at room temperature, and then, compress the curable resin
composition between the mold members while heating by a thermal
press machine. The compression molding temperature is preferably in
the range of 150 to 250.degree. C. The compression molding pressure
is preferably 10 MPa or higher. The holding time is preferably in
the range of 1 to 30 minutes. The cured product may be obtained by,
after taking the compression molded product out from the molds,
subjecting the compression molded product to post curing as
needed.
[0263] One example of the production of the cured product by
transfer molding process is to preform the curable resin
composition in tablets, feed the preformed curable resin
composition to a preheated transfer molding machine, and then,
pressurize and transfer the curable resin composition into a mold
of given shape and material by a plunger of the transfer molding
material. The transfer molding temperature is preferably in the
range of 150 to 250.degree. C. The transfer molding pressure is
preferably in the range of 1 to 50 MPa. The holding time is
preferably in the range of 30 seconds to 20 minutes. The transfer
molding may be performed while depressurizing the inside of the
mold. The cured product may be obtained by, after taking the
transfer molded product out from the mold, subjecting the transfer
molded product to post curing as needed.
[0264] In the case of forming the curable resin composition by
compression molding process, transfer molding process or injection
molding process, a mold release agent may be applied to the mold in
advance. The mold release agent can be of the organic type,
fluorinated type, silicone type etc. Further, the mold release
agent can be in liquid form, spray form, bulk form, tablet form
etc. In the case where the mold release agent is in tablet form, it
is feasible to apply the mold release agent to the mold by forming
the mold release agent before forming the curable resin
composition. As a matter of course, the molding can be performed
without the application of the mold release agent to the mold.
[0265] In the case of transfer molding the curable resin
composition, the gelation time of the curable resin composition is
preferably in the range of 1 to 120 seconds at 150 to 250.degree.
C., especially 1 to 40 seconds at 180.degree. C. The gelation time
refers to a time from the melting to the loss of the flowability or
adhesion during heating of the curable resin composition at a
constant temperature. The gelation time of the curable resin
composition can be measured with the use of a hot plate, a spatula
and a stopwatch. Alternatively, the gelation time of the curable
resin composition can be measured with a torque meter as a time
lapsed until the thickening during heating of the curable resin
composition at a constant temperature. There is no particular
limitation on the type of the torque meter used. Examples of the
torque meter are Curelastometer manufactured by JSR Trading Co.,
Ltd., MDRH 2030 manufactured by M&K Co., Ltd., MDRH Next I
manufactured by Techpro Japan Inc. and VR-3110 manufactured by
Ueshima Seisakusho Co., Ltd. The other measurement conditions are
set so as to comply with EIMS T901: 2006.
[0266] In the case of transfer molding the curable resin
composition, the spiral flow (length) of the curable resin
composition is preferably in the range of 5 to 180 cm at a molding
temperature of 150 to 250.degree. C. It is particularly preferable
that the spiral flow of the curable resin composition is 5 to 180
cm, more preferably 10 to 130 cm, at 180.degree. C. The cured
product as obtained by transfer molding of the curable resin
composition is able to attain good surface smoothness and mold
shape reproducibility without chipping when the spiral flow of the
curable resin composition is in the above specific range. The
spiral flow refers to a numerical value indicating ease of flow of
the curable resin composition during molding and is defined as,
when the curable resin composition is subjected to transfer molding
in a test mold with a spiral flow channel, a length of the curable
resin composition at the time the flow of the curable resin
composition stops. The molding time is set to 3 minutes. The
molding pressure is set to 6.9 MPa. The mold specifications and the
other measurement conditions are set so as to comply with Japan
Electrical Insulating and Advanced Performance Materials Industrial
Association Standard T901 (2006) (abbreviated as EIMS T901:
2006).
[0267] In the case of transfer molding the curable resin
composition, the melt viscosity of the curable resin composition is
preferably in the range of 1 to 500 Pasec at 120 to 250.degree. C.
Herein, the melt viscosity of the curable resin composition is
measured by a constant temperature measurement method with the use
of a flow tester. There is no particular limitation on the type of
the flow tester used. Examples of the flow tester are CFT
manufactured by Shimadzu Corporation and 1548-C manufactured by
Imoto Machinery Co., Ltd. The other measurement conditions are set
so as to comply with EIMS T901: 2006.
[0268] The above gelation time, spiral flow length and melt
viscosity can be adjusted according to the conditions of the
B-staging. The gelation time and spiral flow length decrease with
increase in the temperature and/or time of the B-staging. The melt
viscosity increases with increase in the temperature and/or time of
the B-staging.
[0269] There is no particular limitation on the process of post
curing of the cured product. It is preferable to perform the post
curing by leaving the cured product still in an oven of 150 to
250.degree. C. The time of the heat treatment of the cured product
is preferably 1 hour or longer at 250.degree. C., 2.5 hours or
longer at 200.degree. C. and 3.5 hours or longer at 175.degree.
C.
[0270] In the case of obtaining the cured product by transfer
molding process, the curing speed of the curable resin composition
can be evaluated by the surface smoothness of the cured product. It
is for the reasons that: the surface smoothness of the cured
product not only shows the quality of the cured product but also is
correlated with the mold releasability of the curable resin
composition; and, as is generally known, the mold releasability of
the curable resin composition tends to be correlated with the
curing speed of the curable resin composition. The slower the
curing speed of the curable resin composition, the softer the
molded product after the transfer molding so that, at the time of
release of the mold, a part of the cured product becomes adhered to
the mold to thereby cause deterioration in the surface roughness of
the cured product.
[0271] [Semiconductor Device]
[0272] In the present invention, there is provided a semiconductor
device having at least a semiconductor element encapsulated by the
cured product of the curable resin composition. The other
configuration of the semiconductor device is no particularly
limited. The semiconductor device may be provided with any other
structural component. Examples of the other semiconductor device
component include a base substrate, a lead line, a wiring line, a
control element, an insulating substrate, a heat sink, a conductor,
a die bond material and a bonding pad. Not only the semiconductor
element but also some or all of the semiconductor device components
may be encapsulated by the cured product of the curable resin
composition.
[0273] Herein, there are standards for categorization of power
semiconductor packages by JEDEC (Joint Electron Device Engineering
Counsil), JEITA (Japan Electronics and Information Technology
Industries Association) etc. These standards define package
configurations such as TO-3, TO-92, TO-220, TO-247, TO-252, TO-262,
TO-263 and D2. In the present invention, the semiconductor device
can be provided in any of the above package configurations. The
semiconductor device may be provided as defined by any other
standards.
[0274] One example of the semiconductor device is shown in FIG. 1.
As shown in FIG. 10, the semiconductor device 10 has at least a
power semiconductor element 1, an encapsulant 2, a lead line 3, a
wiring line 4, a base substrate, 5 and an insulating substrate 6.
The power semiconductor element 1 is bonded to the base substrate
vie a die bond material (not shown). The base substrate 5 is
arranged on the insulating substrate 6. A bonding pad of the poser
semiconductor element 1 is electrically connected to the lead line
3 by the wiring line 4. The power semiconductor element 1, the lead
line 3, the wiring line 4, the base substrate 5 and the insulating
substrate 6 are encapsulated by the encapsulant 2.
[0275] The structure of FIG. 1 is merely one example of the
semiconductor device of the present invention. It is feasible to
modify the frame structure of the semiconductor device, the
mounting structure of the semiconductor element etc. as appropriate
and to add the other semiconductor device component as
appropriate.
[0276] [Manufacturing of Semiconductor Device]
[0277] In the present invention, the semiconductor device is
manufactured by cast molding, compression molding or transfer
molding the curable resin composition and encapsulating the
semiconductor element by the cured molded product of the curable
resin composition.
EXAMPLES
[0278] The present invention will be described in more detail below
by way of the following examples. It should be noted that the
following examples are not intended to limit the present invention
thereto.
[0279] <Polysiloxane Compound>
[0280] Polysiloxane compounds were synthesized in the following
synthesis examples and tested for their respective physical
properties by the following methods.
[0281] [Identification of Total Amount of Silanol and Alkoxysilyl
Groups]
[0282] The total amount of silanol and alkoxysilyl Groups in each
synthesized polysiloxane compound was identified by .sup.29Si-NMR
analysis with the use of a 400-MHz nuclear magnetic resonance
spectrometer (manufactured by JEOL Ltd., model: JNM-AL400).
[0283] [Determination of Mass-Average Molecular Weight]
[0284] The mass-average molecular weight (Mw) of each synthesized
polysiloxane compound was determined under the following conditions
by gel permeation chromatography (GPC) on the basis of a
calibration curve using polystyrene as a standard material.
Chromatograph: manufactured by Tosoh Corporation, model:
HLC-8320GPC Column: manufactured by Tosoh Corporation, trade name:
TSK gel Super HZ 2000.times.4, 3000.times.2 Eluent:
tetrahydrofuran
[0285] [Quantification of Structural Unit Composition]
[0286] The composition ratio of a structural unit derived from an
alkoxysilane compound as a raw material in each synthesized
polysiloxane compound was quantified by .sup.1H-NMR and
.sup.29Si-NMR analysis with the use of a 400-MHz nuclear magnetic
resonance spectrometer (manufactured by JEOL Ltd., model:
JNM-AL400).
Synthesis Example 1
Synthesis of Polysiloxane Compound (A-a)
[0287] Into a 2-L four-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 240.40 g (1.000 mol) of
phenyltriethoxysilane and 148.30 g (1.000 mol) of
dimethyldiethoxysilane were placed. Subsequently, 239.64 g of
isopropyl alcohol, 185.02 g of water and 0.12 g of acetic acid were
placed into the flask. The resulting mixture was subjected to
hydrolysis and condensation by stirring while heating the flask at
100.degree. C. After a lapse of 18 hours, the thus-obtained
reaction solution was returned to room temperature. The reaction
solution was then separated into two layers by adding 400 ml of
diisopropyl ether and 400 ml of water to the reaction solution and
stirring the reaction solution. The separated upper layer of the
reaction solution was recovered and washed twice with 400 ml of
water. A slight amount of water dissolved in the diisopropyl ether
was removed by anhydrous magnesium sulfate. After the anhydrous
magnesium sulfate was filtered out, the diisopropyl ether was
distilled out under reduced pressure by an evaporator. By this, the
target polysiloxane compound (A-a) was obtained as a colorless
viscous liquid. The yield of the polysiloxane compound was 182.57
g. The mass-average molecular weight (Mw) of the polysiloxane
compound was 828. The composition of the polysiloxane compound was
[PhSiO.sub.3/2].sub.1.00[Me.sub.2SiO.sub.2/2].sub.0.82. The total
amount of silanol and alkoxysilyl groups in the polysiloxane
compound was 5.76 mmol/g.
Synthesis Example 2
Synthesis of Polysiloxane Compound (A-b)
[0288] Into a 1-L four-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 198.30 g (1.000 mol) of
phenyltrimethoxysilane was placed. Subsequently, 144.00 g of
isopropyl alcohol, 108.00 g of water and 0.072 g of acetic acid
were placed into the flask. The resulting mixture was subjected to
hydrolysis and condensation by stirring while heating the flask at
100.degree. C. After a lapse of 6 hours, the thus-obtained reaction
solution was returned to room temperature. The reaction solution
was then separated into two layers by adding 200 ml of diisopropyl
ether and 200 ml of saturated sodium chloride solution to the
reaction solution and stirring the reaction solution. The separated
upper layer of the reaction solution was recovered and washed twice
with 200 ml of water. A slight amount of water dissolved in the
diisopropyl ether was removed by anhydrous magnesium sulfate. After
the anhydrous magnesium sulfate was filtered out, the diisopropyl
ether was distilled out under reduced pressure by an evaporator. By
this, the target polysiloxane compound (A-b) was obtained as a
colorless solid. The yield of the polysiloxane compound was 135.10
g. The mass-average molecular weight (Mw) of the polysiloxane
compound was 943. The total amount of silanol and alkoxysilyl
groups in the polysiloxane compound was 7.13 mmol/g.
Synthesis Example 3
Synthesis of Polysiloxane Compound (A-c)
[0289] Into a 1-L four-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 136.20 g (1.000 mol) of
methyltrimethoxysilane was placed. Subsequently, 144.00 g of
isopropyl alcohol, 108.00 g of water and 0.072 g of acetic acid
were placed into the flask. The resulting mixture was subjected to
hydrolysis and condensation by stirring while heating the flask at
100.degree. C. After a lapse of 6 hours, the thus-obtained reaction
solution was returned to room temperature. The reaction solution
was then separated into two layers by adding 200 ml of diisopropyl
ether and 200 ml of water to the reaction solution and stirring the
reaction solution. The separated upper layer of the reaction
solution was recovered and washed twice with 200 ml of water. The
diisopropyl ether was distilled out under reduced pressure by an
evaporator. By this, the target polysiloxane compound (A-c) was
obtained as a colorless viscous liquid. The yield of the
polysiloxane compound was 19.66 g. The mass-average molecular
weight Mw of the polysiloxane compound was 932. The total amount of
silanol and alkoxysilyl groups in the polysiloxane compound was
12.5 mmol/g.
Synthesis Example 4
Synthesis of Polysiloxane Compound (A-d)
[0290] Into a 2-L three-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 96.2 g (0.80 mol) of
dimethyldimethoxysilane, 158.6 g (0.80 mol) of
phenyltrimethoxysilane and 52.1 g (0.25 mol) of tetraethoxysilane
were placed. Subsequently, 239.6 g of isopropyl alcohol, 185.0 g of
water and 0.12 g of acetic acid were placed into the flask. The
resulting mixture was subjected to hydrolysis and condensation by
stirring while heating the flask at 100.degree. C. After a lapse of
6 hours, the thus-obtained reaction solution was returned to room
temperature. The reaction solution was then separated into two
layers by adding 400 ml of diisopropyl ether and 400 ml of water to
the reaction solution and stirring the reaction solution. The
separated upper layer of the reaction solution was recovered and
washed twice with 400 ml of water. The diisopropyl ether was
distilled out under reduced pressure by an evaporator. By this, the
target polysiloxane compound (A-d) was obtained as a colorless
viscous liquid. The yield of the polysiloxane compound was 143.4 g.
The mass-average molecular weight Mw of the polysiloxane compound
was 1100. The total amount of silanol and alkoxysilyl groups in the
polysiloxane compound was 7.7 mmol/g.
Synthesis Example 5
Synthesis of Polysiloxane Compound (A-e)
[0291] Into a 2-L three-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 60.11 g (0.50 mol) of
dimethyldimethoxysilane and 68.11 g (0.50 mol) of
methyltrimethoxysilane were placed. Subsequently, 120.0 g of
isopropyl alcohol, 90.0 g of water and 0.060 g of acetic acid were
placed into the flask. The resulting mixture was subjected to
hydrolysis and condensation by stirring while heating the flask at
100.degree. C. After a lapse of 6 hours, the thus-obtained reaction
solution was returned to room temperature. The reaction solution
was then separated into two layers by adding 200 ml of diisopropyl
ether and 200 ml of water to the reaction solution and stirring the
reaction solution. The separated upper layer of the reaction
solution was recovered and washed twice with 200 ml of water. The
diisopropyl ether was distilled out under reduced pressure by an
evaporator. By this, the target polysiloxane compound (A-e) was
obtained as a colorless viscous liquid. The yield of the
polysiloxane compound was 55.0 g. The mass-average molecular weight
Mw of the polysiloxane compound was 618. The total amount of
silanol and alkoxysilyl groups in the polysiloxane compound was
10.1 mmol/g.
Synthesis Example 6
Synthesis of Polysiloxane Compound (A-f)
[0292] Into a 2-L three-neck flask with an agitation blade of
fluororesin and a Dimroth condenser, 30.1 g (0.25 mol) of
dimethyldimethoxysilane and 102.17 g (0.75 mol) of
methyltrimethoxysilane were placed. Subsequently, 132.0 g of
isopropyl alcohol, 99.0 g of water and 0.066 g of acetic acid were
placed into the flask. The resulting mixture was subjected to
hydrolysis and condensation by stirring while heating the flask at
100.degree. C. After a lapse of 24 hours, the thus-obtained
reaction solution was returned to room temperature. The reaction
solution was then separated into two layers by adding 200 ml of
diisopropyl ether and 200 ml of water to the reaction solution and
stirring the reaction solution. The separated upper layer of the
reaction solution was recovered and washed twice with 200 ml of
water. The diisopropyl ether was distilled out under reduced
pressure by an evaporator. By this, the target polysiloxane
compound (A-f) was obtained as a colorless viscous liquid. The
yield of the polysiloxane compound was 64.8 g. The mass-average
molecular weight Mw of the polysiloxane compound was 945. The total
amount of silanol and alkoxysilyl groups in the polysiloxane
compound was 8.8 mmol/g.
[0293] <Silica>
[0294] The physical properties of silica were tested by the
following method.
[0295] [pH Measurement of Silica Extract Water]
[0296] The pH of each silica extract water was determined according
to JIS K 1150: 1994. More specifically, the silica was dried in the
air at 170.degree. C. for 2 hours, weighed by an amount of 10.00 g
and put into the after-mentioned 300-ml beaker. Into the beaker,
200 ml of the after-mentioned purified water was added. The beaker
was then covered by a watch glass. The resulting liquid was stirred
at 80.degree. C. for 1 hour and cooled down to room temperature.
The supernatant liquid was recovered as the silica extract. After
the temperature of the supernatant liquid was set to 25.degree. C.,
the pH value of the supernatant liquid was measured with the
after-mentioned pH meter. Herein, the pH value was read to one
decimal place.
Beaker: hard type, as specified in JIS R 3505 Purified Water:
1.times.10.sup.-3 S/m or lower electric conductivity pH meter:
model D-54 and 9681-10D manufactured by Horiba Ltd., as specified
in JIS Z 8802
[0297] <Curable Resin Composition>
[0298] In Examples of 1 to 28, Comparative Examples 1 to 5 and
Reference Example 1, curable resin compositions were prepared by
the following procedures using the respective components in amounts
as shown in TABLE 1.
[0299] [Kneading of Components]
[0300] In the case of kneading the respective components such as
polysiloxane compound and silica with the use of a mortar, the
respective components were kneaded together in the mortar at room
temperature until the properties of the resulting composition were
judged to be uniform by hand touch. The total amount of the
respective components was adjusted to 60 g or less.
[0301] In the case of kneading the respective components such as
polysiloxane compound and silica with the use of a continuous
kneader, the respective components were subjected to prekneading by
a planetary mixer, and then, kneaded together by the continuous
kneader (S1KRC kneader manufactured by Kurimoto Ltd.). The total
amount of the respective components was adjusted to 300 to 1000 g.
The prekneading was performed in the planetary mixer at room
temperature until the properties of the resulting composition were
judged to be uniform by visual inspection and hand touch. Although
the prekneading time was varied depending on the amount and kind of
the curable resin composition, the kneading time was set to be 20
to 150 minutes. The kneading was performed at 40.degree. C. by
feeding and passing the prekneaded composition one time through the
continuous kneader. The feeding speed of the prekneaded composition
was set to 20 g/min. The rotation speed of the continuous kneader
was set to 300 min.sup.-1. In the case of using two kinds of
silica, these two kinds of silica were mixed together by a
planetary mixer before the prekneading. The mixing time was set to
180 minutes.
[0302] [B-staging of Curable Resin Composition]
[0303] Only in the case of forming the curable resin composition by
transfer molding process, the curable resin composition was
subjected to B-staging by spreading the kneaded composition in a
tray of fluororesin, leaving the tray still in an oven and thereby
heating the kneaded composition. Although the B-staging temperature
and time were varied depending on the kind of the curable resin
composition, the B-staging temperature was set to be 100 to
120.degree. C.; and the B-staging time was set to be 2.5 to 39
hours. By this B-staging treatment, the after-mentioned gelation
time of the curable resin composition was adjusted to 1 to 40
seconds; and the after-mentioned spiral flow length of the curable
resin composition was adjusted to an arbitrary value.
[0304] [Gelation Time Measurement of B-Staged Curable Resin
Composition]
[0305] The gelation time of each B-staged curable resin composition
was determined by the following method.
[0306] A metal plate was heated to 180.degree. C. by a hot plate.
Upon placing 0.5 to 2.0 g of the curable resin composition on the
metal plate, a stopwatch was started for time measurement. During
the time measurement, the curable resin composition was stirred by
a metal spatula. The stopwatch was stopped at the time the curable
resin composition lost its adhesion and became peeled off from the
metal plate. The measured time was read as the gelation time.
[0307] [Tableting of Curable Resin Composition]
[0308] The curable resin composition was tableted by putting 40 g
of the curable resin composition into a cylindrical mold of 38 mm
diameter and press the curable resin composition with a press
machine at room temperature for 10 seconds. The forming pressure
was set to 3 MPa.
[0309] <Evaluation of Tableted Curable Resin Composition>
[0310] The tablets of the curable resin composition, as obtained
above in Examples 1 and 22, were tested for the tablet-to-tablet
adhesion resistance and shape maintenance by the following
methods.
[0311] [Evaluation Test for Adhesion Resistance of Tableted Curable
Resin Composition]
[0312] One of the cylindrical tablets was placed in a horizontal
position with a flat surface thereof oriented downward. On this
tablet, another one of the cylindrical tablets was overlaid with a
flat surface thereof oriented downward. After the two tablets were
left still at room temperature for 24 hours, the upper-side tablet
was lifted up to evaluate the adhesion resistance between the two
tablets. In TABLE 3, the symbol ".largecircle." means that the
adhesion resistance between the tablets was good; and the symbol
".circleincircle." means that the adhesion resistance between the
tablets was very good.
[0313] [Evaluation Test for Shape Maintenance of Tableted Curable
Resin Composition]
[0314] The cylindrical tablet was placed in a horizontal position
with a flat surface thereof oriented downward. After the tablet was
left still at room temperature for 24 hours, the shape of the
tablet was visually checked. In TABLE 3, the symbol ".largecircle."
means that the tablet had good shape maintenance; and the symbol
".circleincircle." means that the tablet had very good shape
maintenance.
[0315] <Forming of Curable Resin Composition and Production of
Cured Product>
[0316] In Examples of 1 to 28, Comparative Examples 1 to 5 and
Reference Example 1, cured products were obtained by subjecting the
respective curable resin compositions to any of the following
forming processes.
[0317] [Cast Molding Process]
[0318] The curable resin composition was fed to a glass or silicon
rubber mold of 21 mm diameter at room temperature, poured in the
mold to a height of 15 mm and thereby subjected to molding. The
cured product was obtained by heat treating the resulting cast
molded product in the mold at 250.degree. C. for 1 hour.
[0319] [Compression Molding Process]
[0320] The curable resin composition was fed into a mold (40
mm.times.60 mm or 100 mm.times.100 mm cavity size) at room
temperature, pressed in the mold while heating at 250.degree. C. by
a thermal press machine (26-ton hydraulic molding machine
manufactured by Toho Seisakusho Co., Ltd.) and thereby subjected to
molding. The molding pressure was set to 50 MPa when the mold was
of 40 mm.times.60 mm cavity size. When the mold was of 100
mm.times.100 mm cavity size, the molding pressure was set to 25
MPa. The cured product was obtained by releasing the resulting
compression molded product from the mold and subjecting the
compression molded product to post curing heat treatment at
250.degree. C. for 1 hour.
[0321] [Transfer Molding Process]
[0322] The tableted product of the curable resin composition was
put in a transfer molding machine (MF-0 manufactured by Marushichi
Engineering Co., Ltd.), which had been heated to 180.degree. C. or
200.degree. C., pressed into a six cavity mold of 10 mm.times.70 mm
cavity size and 3 mm thickness, a single cavity mold of 70
mm.times.70 mm cavity size and 3 mm thickness, a double cavity mold
of 13 mm.times.120 mm cavity size and 3 mm thickness, a double
cavity mold of 13 mm.times.125 mm cavity size and 1.6 mm thickness
or a single cavity mold of 90 mm diameter and 3 mm thickness at 6.9
MPa and 180.degree. C. or 200.degree. C. for 15 minutes and thereby
subjected to molding. The mold was used with the application of a
mold release agent (trade name: Daifree, manufactured by Daikin
Industries, Ltd.). The cured product was obtained by releasing the
resulting transfer molded product from the mold and subjecting the
transfer molded product to post curing heat treatment at
250.degree. C. for 1 hour.
[0323] [Spin Coating Process]
[0324] A film of the curable resin composition, which consisted
only of the polysiloxane compound, was formed by dropping the
curable resin composition onto a silicon substrate of 100 mm
diameter and rotating the silicon substrate with a spin coater at
500 rpm for 10 seconds. The cured product was obtained by heat
treating the film of the curable resin composition on the substrate
at 250.degree. C. for 1 hour.
[0325] <Evaluation of Cured Product>
[0326] The cured products of Examples 1-28, Comparative Examples
1-4 and Reference Example 1 were tested for the occurrence of
foaming by the following method.
[0327] [Evaluation Test for Foaming Occurrence of Cured
Product]
[0328] The cured product was checked by visual inspection. In TABLE
1, the wording "not occur" means that no foaming was seen in the
cured product; and the wording "occur" means that foaming was seen
in the cured product.
[0329] The cured products of Examples 8-16 and 23-24 were tested
for the surface smoothness by the following method.
[0330] [Evaluation Test for Surface Smoothness of Cured
Product]
[0331] The surface of the cured product was checked by finger
touch. In TABLES 2 and 4, the symbol ".largecircle." means that the
cured product had good surface smoothness; and the symbol
".circleincircle." means that the cured product had very good
surface smoothness.
[0332] The cured products of Examples 11, 13-16 and 23-24 were
tested for the non-occurrence of chipping by the following
method.
[0333] [Evaluation Test for Chipping Non-Occurrence of Cured
Product]
[0334] The cured product was checked by visual inspection. In TABLE
4, the symbol ".largecircle." means that the occurrence of chipping
in the cured product was not almost detected; and the symbol
".circleincircle." means that the occurrence of chipping in the
cured product was not particularly detected.
[0335] The cured product of Example 3 was tested for the heat
resistance by the following method.
[0336] [Evaluation Test for Heat Resistance of Cured Product]
[0337] The cured product was heated at 250.degree. C. until the
lapse of 2000 hours. The weight of the cured product before and
after the heating was measured to evaluate the rate of weight
change of the cured product relative to the heating time. The
evaluation test result is shown in FIG. 2.
Examples 1-28 and Comparative Examples 1-4
[0338] As shown in TABLE 1, the curable resin compositions of
Examples 1-28 falling within the scope of the present invention and
the curable resin compositions of Comparative Examples 1-4 falling
outside the scope of the present invention were respectively formed
and cured. The sizes and foaming evaluation results of the
resulting cured products are shown in TABLE 1. The respective
curable resin compositions for evaluation were each prepared by
mixing any of the polysiloxane compounds (A-a) to (A-f) synthesized
in Synthesis Examples 1-6, the specific silica component and the
specific additive component in amounts as shown in TABLE 1.
Comparative Example 5
[0339] As shown in TABLE 1, the curable resin composition of
Comparative Example 5 falling outside the scope of the present
invention was formed. However, the cured product was not obtained
in bulk form, but was obtained in powder form, after the heat
treatment.
Reference Example 1
[0340] As shown in TABLE 1, the curable resin composition of
Reference Example 1, which consisted only of the polysiloxane
compound (A-a), was formed and cured into a film shape of 100 mm
diameter and 0.1 mm thickness.
TABLE-US-00001 TABLE 1 Composition Polysiloxane Silica Additive
Cured product pts. pts. pts. Forming size (mm, kind mass kind pH
mass kind mass process t: thickness) foaming Ex. 1 A-a 17 SO-C2 4.8
83 -- -- cast molding .phi.21 .times. t15 not occur Ex. 2 A-a 25
SO-C2 4.8 75 -- -- cast molding .phi.21 .times. t15 not occur Ex. 3
A-a 10 FB-20D 6.0 90 -- -- cast molding .phi.21 .times. t15 not
occur Ex. 4 A-a 10 FB-20D 6.0 90 #30L 0.1 compression 40 .times. 60
.times. t4 not occur molding Ex. 5 A-a 10 FB-20D 6.0 90 #30L 0.1
compression 100 .times. 100 .times. t2 not occur molding Ex. 6 A-a
6 ML-902SK 5.5 94 -- -- cast molding .phi.21 .times. t15 not occur
Ex. 7 A-a 10 ML-902SK 5.5 90 -- -- cast molding .phi.21 .times. t15
not occur Ex. 8 A-a 15 ML-902SK 5.5 85 #30L 0.1 transfer 10 .times.
70 .times. t3 not occur molding Ex. 9 A-a 15 mixed 5.4 85 #30L 0.1
transfer 10 .times. 70 .times. t3 not occur silica B-a molding Ex.
10 A-a 15 mixed 5.4 85 #30L 0.1 transfer 10 .times. 70 .times. t3
not occur silica B-a molding Ex. 11 A-a 12 mixed 5.4 88 #30L 0.1
transfer 10 .times. 70 .times. t3 not occur silica B-a molding Ex.
12 A-a 10 mixed 5.4 90 #30L 0.1 transfer 10 .times. 70 .times. t3
not occur silica B-a molding Ex. 13 A-a 12 mixed 5.4 88 #30L 0.1
transfer 70 .times. 70 .times. t3 not occur silica B-a molding Ex.
14 A-a 12 mixed 5.4 88 #30L 0.1 transfer 13 .times. 120 .times. t3
not occur silica B-a molding Ex. 15 A-a 12 mixed 5.4 88 #30L 0.1
transfer 13 .times. 125 .times. t1.6 not occur silica B-a molding
Ex. 16 A-a 12 mixed 5.4 88 #30L 0.1 transfer .phi.90 .times. t3 not
occur silica B-a molding Ex. 17 A-b 10 ML-902SK 5.5 90 -- -- cast
molding .phi.21 .times. t15 not occur Ex. 18 A-c 10 ML-902SK 5.5 90
-- -- cast molding .phi.21 .times. t15 not occur Ex. 19 A-d 12
mixed 5.4 88 #30L 0.1 cast molding .phi.21 .times. t15 not occur
silica B-a Ex. 20 A-e 12 mixed 5.4 88 #30L 0.1 cast molding .phi.21
.times. t15 not occur silica B-a Ex. 21 A-f 12 mixed 5.4 88 #30L
0.1 cast molding .phi.21 .times. t15 not occur silica B-a Ex. 22
A-a 12 mixed 5.4 88 #30L 0.1 transfer 10 .times. 70 .times. t3 not
occur silica B-a CP-102 1 molding Ex. 23 A-a 12 mixed 5.4 88 #30L
0.1 transfer 10 .times. 70 .times. t3 not occur silica B-a molding
Ex. 24 A-a 12 mixed 5.4 88 #30L 0.1 transfer 10 .times. 70 .times.
t3 not occur silica B-a molding Ex. 25 A-a 10 SE-15K 5.9 90 -- --
cast molding .phi.21 .times. t15 not occur Ex. 26 A-a 10 MSR-LV24
5.4 90 -- -- cast molding .phi.21 .times. t15 not occur Ex. 27 A-a
10 MSR-5100 5.3 90 -- -- cast molding .phi.21 .times. t15 not occur
Ex. 28 A-a 10 EMIX-CER 5.4 90 -- -- cast molding .phi.21 .times.
t15 not occur Comp. A-a 100 -- -- 0 -- -- cast molding .phi.21
.times. t15 occur Ex. 1 Comp. A-a 33 SO-C2 4.8 67 -- -- cast
molding .phi.21 .times. t15 occur Ex. 2 Comp. A-a 25 SC2500-SQ 6.3
75 -- -- cast molding .phi.21 .times. t15 occur Ex. 3 Comp. A-a 17
SC5500-SQ 6.8 83 -- -- cast molding .phi.21 .times. t15 occur Ex. 4
Comp. A-a 2 ML-902SK 5.5 98 -- -- cast molding -- -- Ex. 5 Ref. A-a
100 -- -- 0 -- -- spin coating .phi.100 .times. t0.1 not occur Ex.
1 [Silica] SO-C2: deflagration silica, median size: 0.5 .mu.m,
manufactured by Admatechs; FB-20D: natural fused silica, median
size: 23 .mu.m, manufactured by Denka Company Limited.; ML-902SK:
synthetic fused silica, median size: 24 .mu.m, manufactured by
Tokuyama Corporation; SC2500-SQ: deflagration silica, median size:
0.5 .mu.m, manufactured by Admatechs; SC5500-SQ: deflagration
silica, median size: 1.5 .mu.m, manufactured by Admatechs; SE-15K:
synthetic fused silica, median size: 18 .mu.m, manufactured by
Tokuyama Corporation; MSR-LV24: natural fused silica, median size:
23 .mu.m, manufactured by Tatsumori Ltd.; MSR-5100: natural fused
silica, median size: 16 .mu.m, manufactured by Tatsumori Ltd.;
EMIX-CER: synthetic fused silica, median size: 20 .mu.m,
manufactured by Tatsumori Ltd.; mixed silica: ML-902SK/SO-C2 = 95/5
(pts. mass) [Additive] #30L: carbon black manufactured by
Mitsubishi Chemistry Corporation; CP-102: fumed silica manufactured
by Tokuyama Corporation [Compression Molding Process] Equipment:
26-ton hydraulic molding machine manufactured by Toho Seisakusho
Co., Ltd.; Molding conditions: 250.degree. C., 50 MPa (Example 4)
or 25 MPa (Example 5), 15 min. [Transfer Molding Process]
Equipment: transfer molding machine MF-0 manufactured by Marushichi
Engineering Co., Ltd.; Molding conditions: 200.degree. C. (Examples
8-9) or 180.degree. C. (Examples 10-16 and 22-24), 6.9 MPa, 15 min.
[Spiral Flow of Curable Resin Composition] Measurement conditions:
180.degree. C., 6.9 MPa, 3 min.; Measured value: 80 cm (Examples 11
and 13-16), 8 cm (Example 23), 134 cm (Example 24)
[0341] In Comparative Example 1 and Reference Example 1 of TABLE 1,
it is shown the case where the cured products were obtained using
only the polysiloxane compound (A-a). Foaming was seen in the cured
product of Comparative Example 1 having a relatively large size of
21 mm diameter and 15 mm thickness. By contrast, no foaming was
seen in the cured product of Reference Example 1 having a thin film
shape of 100 mm diameter and 0.1 mm thickness. In the case where
the cured products were obtained with a diameter of 21 mm and a
thickness of 15 mm, foaming was seen in all of the cured products
of Comparative Examples 1-4; whereas foaming was not seen in any of
the cured products of Examples 1-3, 6-7, 17-21 and 25-28. In the
case where the cured product was obtained from the curable resin
composition in which the pigment was added as the additive, foaming
was not also seen in the cured product as shown in Examples 4-5,
8-16 and 19-24. As shown in Example 22, foaming was not also seen
in the cured product in the case where the cured product was
obtained from the curable resin composition in which the
anti-blocking agent was added as the additive. It is apparent from
these results that the curable resin composition falling within the
scope of the present invention was, even when formed in a large
thickness and large area, free of the occurrence of foaming.
[0342] In the case of using the silica components whose extract
waters were the same in pH, there was a difference between the
occurrence and non-occurrence of foaming in the cured products
depending on the polysiloxane-to-silica component ratios of the
curable resin compositions as shown in Examples 1-2 and Comparative
Example 2.
[0343] In the case where the polysiloxane-to-silica component
ratios of the curable resin compositions were the same, on the
other hand, foaming was not seen in the cured product using the
silica component whose extract water was low in pH; whereas foaming
was seen in the cured product using the silica component whose
extract water was high in pH, as shown in Examples 1-2 and
Comparative Examples 3-4.
[0344] As shown in Examples 1-28, foaming was not seen in the cured
products in the case where the cured products were obtained from
the curable resin compositions in which the structural units and
component ratios of the polysiloxane compounds were different.
[0345] Further, foaming was not seen in the cured products in the
case where the cured products were obtained by the adoption of any
of cast molding process, compression molding process and transfer
molding process as shown in Examples 1-28.
Examples 8-16
Evaluation of Surface Smoothness of Cured Product
[0346] Among the examples of TABLE 1, evaluations were made as to
the surface roughness of the cured products obtained by transfer
molding the curable resin compositions (Examples 8-16). The
evaluation results are shown in TABLE 2.
TABLE-US-00002 TABLE 2 Composition Transfer Polysiloxane Silica
Additive molding Cured product pts. pts. pts. temperature size (mm,
surface kind mass kind pH mass kind mass (.degree. C.) t:
thickness) smoothness Ex. 8 A-a 15 ML-902SK 5.5 85 #30L 0.1 200 10
.times. 70 .times. t3 .largecircle. Ex. 9 A-a 15 mixed 5.4 85 #30L
0.1 200 10 .times. 70 .times. t3 .circleincircle. silica B-a Ex. 10
A-a 15 mixed 5.4 85 #30L 0.1 180 10 .times. 70 .times. t3
.circleincircle. silica B-a Ex. 11 A-a 12 mixed 5.4 88 #30L 0.1 180
10 .times. 70 .times. t3 .circleincircle. silica B-a Ex. 12 A-a 10
mixed 5.4 90 #30L 0.1 180 10 .times. 70 .times. t3 .circleincircle.
silica B-a Ex. 13 A-a 12 mixed 5.4 88 #30L 0.1 180 70 .times. 70
.times. t3 .circleincircle. silica B-a Ex. 14 A-a 12 mixed 5.4 88
#30L 0.1 180 13 .times. 120 .times. t3 .circleincircle. silica B-a
Ex. 15 A-a 12 mixed 5.4 88 #30L 0.1 180 13 .times. 125 .times. t1.6
.circleincircle. silica B-a Ex. 16 A-a 12 mixed 5.4 88 #30L 0.1 180
.phi.90 .times. t3 .circleincircle. silica B-a [Silica] SO-C2:
deflagration silica, median size: 0.5 .mu.m, manufactured by
Admatechs; ML-902SK: synthetic fused silica, median size: 24 .mu.m,
manufactured by Tokuyama Corporation; mixed silica: ML-902SK/SO-C2
= 95/5 (pts. mass) [Additive] #30L: carbon black manufactured by
Mitsubishi Chemistry Corporation; [Molding Process: Transfer
Molding] Equipment: transfer molding machine MF-0 manufactured by
Marushichi Engineering Co., Ltd.; Molding conditions: 6.9 MPa, 15
min.
[0347] As shown in Examples 8 and 9 of TABLE 2, the cured product
had better surface roughness when mixed silica (B-a) containing 95
mass % of synthetic fused silica (median size: 24 .mu.m, trade
name: ML-902SK) and 5 mass % of deflagration silica (median size:
0.5 .mu.m, trade name: SO-C2) was used as the silica component than
when only synthetic fused silica (median size: 24 .mu.m, trade
name: ML-902SK) was used as the silica component. Even though the
molding temperature was lower in Example 10 than in Example 8, the
cured product of Example 10 using the mixed silica (B-a) had better
surface roughness. It is apparent from these results that, as
compared to the case where only large particle size silica was used
as the silica component, the curing speed of the curable resin
composition was increased to allow improvement of mold
releasability and decrease of forming temperature by the addition
of small particle size silica.
[0348] The cured products of Examples 10-12 had very good surface
smoothness even though the component ratios of the curable resin
compositions were varied. The curing speed increasing effects of
the addition of small particle size silica were confirmed by these
results. Similarly, the same effects were confirmed even when the
sizes of the cured products were varied.
Examples 11 and 22
Evaluation of Adhesion Resistance and Shape Maintenance of
Tablets
[0349] Among the examples of TABLE 1, evaluations were made as to
the adhesion resistance and shape maintenance of the tablets
obtained by transfer molding the curable resin compositions
(Examples 11 and 22). The evaluation results are shown in TABLE
3.
TABLE-US-00003 TABLE 3 Composition Tablet Polysiloxane Silica
Additive (40 g, .phi.38 mm) pts. pts. pts. suppression shape kind
mass kind pH mass kind mass of adhesion maintenance Ex. 11 A-a 12
mixed 5.4 88 #30L 0.1 .largecircle. .largecircle. silica B-a Ex. 22
A-a 12 mixed 5.4 88 #30L 0.1 .circleincircle. .circleincircle.
silica B-a CP-102 1 [Silica] SO-C2: deflagration silica, median
size: 0.5 .mu.m, manufactured by Admatechs; ML-902SK: synthetic
fused silica, median size: 24 .mu.m, manufactured by Tokuyama
Corporation; mixed silica: ML-902SK/SO-C2 = 95/5 (pts. mass)
[Additive] #30L: carbon black manufactured by Mitsubishi Chemistry
Corporation; CP-102: fumed silica manufactured by Tokuyama
Corporation [Molding Process: Transfer Molding] Equipment: transfer
molding machine MF-0 manufactured by Marushichi Engineering Co.,
Ltd.; Molding conditions: 6.9 MPa, 15 min.
[0350] As shown in Examples 11 and 22 of TABLE 3, the tablet in
which the anti-blocking agent was used as the additive had better
tablet-to-tablet adhesion resistance and shape maintenance than the
tablet in which the anti-blocking agent was not used as the
additive.
Examples 11, 13-16 and 23-24
Evaluation of Surface Smoothness and Chipping Non-Occurrence of
Cured Product
[0351] Among the examples of TABLE 1, evaluations were made as to
the surface smoothness and chipping non-occurrence of the cured
products obtained by transfer molding the curable resin
compositions (i.e. in Examples 11, 13-16 and 23-24). The evaluation
results are shown in TABLE 4.
TABLE-US-00004 TABLE 4 Composition Cured product Polysiloxane
Silica Additive Spiral surface non- pts. pts. pts. flow size (mm,
rough- occurrence kind mass kind pH mass kind mass (cm) t:
thickness) ness of chipping Ex. 11 A-a 12 mixed 5.4 88 #30L 0.1 80
10 .times. 70 .times. t3 .circleincircle. .circleincircle. silica
B-a Ex. 13 A-a 12 mixed 5.4 88 #30L 0.1 80 70 .times. 70 .times. t3
.circleincircle. .circleincircle. silica B-a Ex. 14 A-a 12 mixed
5.4 88 #30L 0.1 80 13 .times. 120 .times. t3 .circleincircle.
.circleincircle. silica B-a Ex. 15 A-a 12 mixed 5.4 88 #30L 0.1 80
13 .times. 125 .times. t1.6 .circleincircle. .circleincircle.
silica B-a Ex. 16 A-a 12 mixed 5.4 88 #30L 0.1 80 .phi.90 .times.
t3 .circleincircle. .circleincircle. silica B-a Ex. 23 A-a 12 mixed
5.4 88 #30L 0.1 8 10 .times. 70 .times. t3 .circleincircle.
.largecircle. silica B-a Ex. 24 A-a 12 mixed 5.4 88 #30L 0.1 134 10
.times. 70 .times. t3 .largecircle. .circleincircle. silica B-a
[Silica] SO-C2: deflagration silica, median size: 0.5 .mu.m,
manufactured by Admatechs; ML-902SK: synthetic fused silica, median
size: 24 .mu.m, manufactured by Tokuyama Corporation; mixed silica:
ML-902SK/SO-C2 = 95/5 (pts. mass) [Additive] #30L: carbon black
manufactured by Mitsubishi Chemistry Corporation; [Molding Process:
Transfer Molding] Equipment: transfer molding machine MF-0
manufactured by Marushichi Engineering Co., Ltd.; Molding
conditions: 180.degree. C., 6.9 MPa, 15 min. [Spiral Flow of
Curable Resin Composition] Measurement conditions: 180.degree. C.,
6.9 MPa, 3 min.
[0352] As shown in Examples 11, 13-16 and 23 of TABLE 4, the
occurrence of chipping in the cured product was less detected when
the spiral flow of the curable resin composition was adjusted to 80
cm than when the spiral flow of the curable resin composition was
adjusted to 8 cm, even though where the component ratios of the
curable resin compositions were the same.
[0353] Further, the surface smoothness of the cured product was
better when the spiral flow of the curable resin composition was
adjusted to 80 cm than when the spiral flow of the curable resin
composition was adjusted to 134 cm, even though the component
ratios of the curable resin compositions were the same, as shown in
Examples 11, 13-16 and 24 of TABLE 4.
[0354] The cured products of Examples 11 and 13-16, each of which
was obtained by adjusting the spiral flow of the curable resin
composition to 80 cm, had particularly no chipping occurrence and
very good surface smoothness even though varied in size as shown in
TABLE 4.
[0355] Furthermore, the cured product of Example 3 had a weight
change rate of -0.55 mass % even after heated at 250.degree. C. for
a long term of 2000 hours and showed substantially no weight
decrease as shown in FIG. 2.
* * * * *